Re: Adding Slots for CP volumes in the System Config file
Thanks, Kris - of course, you're right. Because I always add many Reserved slots, that practice lead me to 'mis-remember'. Thanks again. Maybe the next z/VM release will come with all 255 slots allocated or pre-Reserved? ;-) Mike Walter Hewitt Associates - Original Message - From: Kris Buelens [kris.buel...@gmail.com] Sent: 02/11/2009 08:45 AM CET To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Adding Slots for CP volumes in the System Config file Believes can be faint: -You cannot define new slots on the fly. -You can fill in the predefined slots on the fly. That's the reason you define reserved slots in SYSTEM CONFIG. 2009/2/11 Mike Walter mike.wal...@hewitt.com: I believe that there are CP commands to DEFINE new CP_OWNED slots dynamically. But I'm sitting on the couch typing on a Blackberry, so have not checked the CP Commands and Utilities manual. I'm getting older and could be misremembering. Mike Walter Hewitt Associates From: Martin, Terry R. (CMS/CTR) (CTR) [terry.mar...@cms.hhs.gov] Sent: 02/10/2009 11:20 PM EST To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Adding Slots for CP volumes in the System Config file Thanks Mike. I am adding the SLOTS for paging! You do believe there is a way to add the SLOTS on the fly? Terry -- Kris Buelens, IBM Belgium, VM customer support The information contained in this e-mail and any accompanying documents may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message, including any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited. All messages sent to and from this e-mail address may be monitored as permitted by applicable law and regulations to ensure compliance with our internal policies and to protect our business. E-mails are not secure and cannot be guaranteed to be error free as they can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by e-mail.
Adding Slots for CP volumes in the System Config
No, you cannot define new slots on the fly. 255 slots consume about 4 contiguous pages of storage. I believe that there are CP commands to DEFINE new CP_OWNED slots = dynamically. But I'm sitting on the couch typing on a Blackberry, so have = not checked the CP Commands and Utilities manual. I'm getting older and = could be misremembering. Richard Corak
Paging
Were there any EREP messages? Any report of where the bad spot on DASD might be? It could be instructive to examine the track in question, if it can be identified. Richard Corak
Re: Adding Slots for CP volumes in the System Config file
check your System Config and see what your next reserved slot is: enter - DEF CPOWN SLOT nnn volid with nnn being the next reserved slot and the pack is not attached to the system after the define attach it to the system and it will be found. like Mike said be sure you add it into the System Config also and also add a LOT of reserved slots. good luck Bill Munson Sr. z/VM Systems Programmer Brown Brothers Harriman CO. 525 Washington Blvd. Jersey City, NJ 07310 201-418-7588 President MVMUA http://www2.marist.edu/~mvmua/ Mike Walter mike.wal...@hewitt.com Sent by: The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU 02/10/2009 11:36 PM Please respond to The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU To IBMVM@LISTSERV.UARK.EDU cc Subject Re: Adding Slots for CP volumes in the System Config file I believe that there are CP commands to DEFINE new CP_OWNED slots dynamically. But I'm sitting on the couch typing on a Blackberry, so have not checked the CP Commands and Utilities manual. I'm getting older and could be misremembering. Mike Walter Hewitt Associates From: Martin, Terry R. (CMS/CTR) (CTR) [terry.mar...@cms.hhs.gov] Sent: 02/10/2009 11:20 PM EST To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Adding Slots for CP volumes in the System Config file Thanks Mike. I am adding the SLOTS for paging! You do believe there is a way to add the SLOTS on the fly? Terry From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mike Walter Sent: Tuesday, February 10, 2009 11:15 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Adding Slots for CP volumes in the System Config file Yep, easy as that -- just DO NOT change the SLOT number on any volumes allocated with SPOOL space!! No significant overhead in the 255 max slots. Changes will be effective at the next IPL, but I believe that there are dynamic CP commands to get you going without an IPL. Remember that you only need CP_Owned slots for volumes with CP space allocated thereon. Volumes with all PERM space do not need to be in the CP_Owned list. Mike Walter Hewitt Associates From: Martin, Terry R. (CMS/CTR) (CTR) [terry.mar...@cms.hhs.gov] Sent: 02/10/2009 11:00 PM EST To: IBMVM@LISTSERV.UARK.EDU Subject: Adding Slots for CP volumes in the System Config file Hi I have a quick question. I need to add more SLOTS in the SYSTEM CONFIG file I am assuming that it is as easy as duplicating existing reserved SLOTS. Is this a fair assumption? Also I believe the max number of SLOTS is 256 is this correct? One last thing is there any performance or other implications to be aware of when increasing the number of SLOTS? Thanks in advance for your help!! Terry The information contained in this e-mail and any accompanying documents may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message, including any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited. All messages sent to and from this e-mail address may be monitored as permitted by applicable law and regulations to ensure compliance with our internal policies and to protect our business. E-mails are not secure and cannot be guaranteed to be error free as they can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by e-mail. The information contained in this e-mail and any accompanying documents may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message, including any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited. All messages sent to and from this e-mail address may be monitored as permitted by applicable law and regulations to ensure compliance with our internal policies and to protect our business. E-mails are not secure and cannot be guaranteed to be error free as they can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by e-mail. *** IMPORTANT NOTE* The opinions expressed in this message and/or any attachments are those of the author and not necessarily those of Brown Brothers Harriman Co., its subsidiaries and affiliates (BBH). There is no guarantee that this message is either private or confidential, and it may have been
Re: DFDSS Dump VM formatted volumes
On Tuesday, 02/10/2009 at 02:18 EST, Brian France b...@psu.edu wrote: We use FDR here. Run CPFMTXA to put an index vtoc on the vol at 0 that z/OS can see. FDR then just dumps the entire volume. Once, we did not do CPFMTXA and z/OS could not handle the volume. Had to run CPFMTXA on the 0 - 1 cyls to put that index vtoc out there. Um, not all volumes have a VTOC on cyl 0. A guest can have cyl 0 and it is not *required* to have a VTOC. If you write one, you may well overlay user data. Of course, if there is no VTOC, the VTOC pointer will be blank (if it is a VOL1 label) or, more likely, it will not be VOL1. FDR/DFDSS need to handle these cases. There's a reason that volume labels follow a set of standards! :-) Alan Altmark z/VM Development IBM Endicott
Re: Adding Slots for CP volumes in the System Config file
On Wednesday, 02/11/2009 at 08:12 EST, Mike Walter mike.wal...@hewitt.com wrote: Maybe the next z/VM release will come with all 255 slots allocated or pre-Reserved? ;-) In the IBM-provided SYSTEM CONFIG, yes. We came to the same conclusion. If you add CP_Owned Slot 256 RESERVED you will automatically reserve all remaining slots. As Richard notes, it's not worth 4 contiguous pages. (All undefined slots between any two defined slots will automatically be RESERVED.) Alan Altmark z/VM Development IBM Endicott
Re: Adding Slots for CP volumes in the System Config file
2009/2/11 Bill Munson william.mun...@bbh.com: check your System Config and see what your next reserved slot is: enter - DEF CPOWN SLOT nnn volid No, to find the next reserved slot, issue CP Q CPOWNED (your SYSTEM CONFIG may already have been updated to be prepare extra slots for the next IPL) -- Kris Buelens, IBM Belgium, VM customer support
Re: Paging
Hi Marcy, Thanks. On this particular LPAR I have 71GB of real memory. Thank You, Terry Martin Lockheed Martin - Information Technology z/OS z/VM Systems - Performance and Tuning Cell - 443 632-4191 Work - 410 786-0386 terry.mar...@cms.hhs.gov -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Marcy Cortes Sent: Tuesday, February 10, 2009 11:36 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Paging I'm pretty sure, like 99.5%, that you can see this error by running out and not just screwing up your space somehow. IBM could probably tell you for sure probably... Remember, by the time you issue the q alloc, the situation could have already come and gone. You didn't say say now much real memory you have, but that one 40G guest should have you at somewhere 35-40 mod 3's. You're going to either have to add HW in the form of paging devices or more real memory. Or shrink your guests significantly (always something to be looked at over and over in the z/VM env.). Marcy This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation. From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Martin, Terry R. (CMS/CTR) (CTR) Sent: Tuesday, February 10, 2009 7:53 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: [IBMVM] Paging Hi I have searched high and low and cannot for the life of me see anything that would have caused the page errors. These packs are not being accessed by any other user of LPAR and from all indications no cylinders have been overwritten. These two packs were bran new and formatted for the first time with CPFMTXA as page volumes. I guess my question is should I put a DRAIN on them before something tries to use them again and once/if drained remove them and re-init them and add them back? I am assuming that I will continue to see the page errors if these page packs are still being used correct? To sum this all up the page slots that are in use in my case adds up to about 39% of all the pages in use will not be reclaimed or paged in by the Linux guest until either the guest is recycled or the LPAR is IPL'ed is this a correct assumption for the most part? Now I see why so many page data sets are required for this z/Linux environment, interesting Terry From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of David Boyes Sent: Tuesday, February 10, 2009 7:04 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Paging That tells me that you allocated them correctly. The question is whether DSF actually wrote CP-compatible blocks (which are different than what minidisks use) on every cylinder. That's one of the reasons why I always add paging areas in full packs, and always run DSF on them, even if they're brand new or already been formatted by Some Other OS. From the other conversation, you may have ended up with a minidisk overlapping a paging area. In either case, you should reformat the disks in question next time you IPL and have the system down for any period (can't do it while it's up if pages have actually been written to the paging areas; CP doesn't really give you an easy way to force migration of pages off a pack if they are still referenced by something). Taking the problem volumes offline and bringing the system up to the point of having OPERATOR logged in but before AUTOLOG1 comes up would be one way to safely reformat them without going to standalone DSF. As Marcy said, though: you are very light on paging space for guests of the size you describe. You probably should wheedle some more paging packs from your storage guys. --d b On 2/10/09 5:23 PM, Martin, Terry R. (CMS/CTR) (CTR) terry.mar...@cms.hhs.gov wrote: Hi Yes, I formatted them using CPFMTXA. The output from the format showed that 0 0 PERM and 1 END PAGE. Thank You, Terry Martin Lockheed Martin - Information Technology z/OS z/VM Systems - Performance and Tuning Cell - 443 632-4191 Work - 410 786-0386 terry.mar...@cms.hhs.gov From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of David Boyes Sent: Tuesday, February 10, 2009 2:56 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Paging Did you format the new paging disks with DSF or CPFMTXA before you attached them to SYSTEM? If you didn't, then that's the cause of the problem. received the following error just before the guest came down: HCP415E Six continuous paging errors have occurred on DASD volume volser. This error occurred on the two
SHARE in Austin-Call for Session Chairs - Part deux!
SHARE in Austin is in less than three weeks! It's that time again to recruit session chairs. As a session chair you'll be the envy of your friends and colleagues. You get to meet and introduce the speaker, make a really cool, but short, speech, count session attendees, keep general order and collect the always important evaluation forms at the end of the session. Feel free to sign up for any sessions you think you may plan to attend. To go along with the SHARE themes, one of which is Total Enterprise Virtualization, the Linux and VM Program is featured prominently in a new Virtualization theme room with a separate set of sessions. These sessions are listed along with the sessions below with a V after the session number. We ask that there be two chairs for each of these sessions. The remaining sessions, in time sequence, are: 9102VMon09:30a930Introduction to Virtualization: z/VM Basic Concepts and TermsBill Bitner 9060VMon11:00a1100IBM Transformation: Major IT Consolidation Initiative for Project Big GreenBill Reeder 9165Mon01:30p1330How to configure your EMC Symmetrix for z/VM and Linux Gail Riley 9127Mon03:00p1500z/VM for MVS Systems Programmers - Part 1 of 2 Martha McConaghy/Mark Post 9241Mon03:00p1500Securing Linux with RACF on z/VMAlan Altmark 9220VMon04:30p1630Nothing Runs Like z/VM and Linux at John Deere Thomas Stewart 9286Mon04:30p1630Tending the SANity of the Flock - SAN Experiences at Nationwide Rick Troth 9234Mon04:30p1630Managing Linux under z/VM using the Linux Performance Suite (ESALPS)Barton Robinson 9128Mon04:30p1630z/VM for MVS Systems Programmers - Part 2 of 2 Martha McConaghy/Mark Post 9293Tue08:00a800What's New in Red Hat Enterprise Linux 5 Bradford Hinson 9277Tue09:30a930Fedora for System z: The Open Source Build Process Explained Bradford Hinson 9202VTue11:00a1100Linux on System z - A Strategic ViewJim Elliott 9124VTue01:30p1330Experiences Using z/VM VSWITCHDavid Kreuter 9292Tue01:30p1330Performance Experience with Databases on Linux for IBM System z Eberhard Pasch 9134Tue03:00p1500Dynamically Managing Hardware I/O Configuration Using VMRick Barlow 9163VTue03:00p1500Sharing the Wealth Using VLANs on Vswitch David Kreuter 9249Tue04:30p1630Putting Linux on System z into Production: True Stories Erich Amrehn 9240Tue04:30p1630Linux on z/VM System Programmer Survival Guide Robert (Jay) Brenneman 9158VWed08:00a800Server Virtualization Technical and Total Cost Analysis Montgomery Bauman 9215Wed09:30a930Linux on System z at Wells Fargo: Penguins Board the Stagecoach Marcy Cortes 9279Wed11:00a1100Problem Determination with Linux on System z Frank Blaschka 9166Wed01:30p1330z/VM Performance Case StudiesBill Bitner 9129Wed03:00p1500z/VM Security and IntegrityAlan Altmark 9146Wed03:00p1500Using Unicenter VM:Operator To Manage Linux Servers Brian Jagos 9273Wed03:00p1500Linux on z/VM Performance casesRob van der Heij 9259Wed04:30p1630SCSI over FCP for Linux on System z - Introduction and New FeaturesChristof Schmitt 9137VThu08:00a800Virtual Linux Server Disaster Recovery Planning Rick Barlow 9224Thu08:00a800Linux System Management for the Mainframe System Programmer - Part 1 of 2Mark Post 9118Thu09:30a930Servicing and Maintaining z/VM with VM/SES - Live Demo Jim Vincent 9267Thu11:00a1100Networking with Linux on System z Frank Blaschka 9281Thu01:30p1330OpenSolaris on System zNeale Ferguson 9212VThu03:00p1500Success with Linux on System z at Nationwide - Leasons LearnedJim Vincent 9290Thu03:00p1500Managing Your Red Hat Enterprise Linux Guests with RHN Satellite Bradford Hinson 9239Thu03:00p1500Linux for System z Goody BagRobert (Jay) Brenneman 9289Fri08:00a800Additional Feet for the Penguin - SCSI over FCP Multipathing for Linux on System zChristof Schmitt 9287Fri08:00a800Installing a Novell SLES 10 Starter System without a Net(work)Mark Post 9270Fri08:00a800Using Linux on System z for Web 2.0 - Infrastructure Wolfgang Taphorn 9274Fri09:30a930The Linux IPL ProcedureEdmund MacKenty -- Rich Smrcina VM Assist, Inc. Phone: 414-491-6001 Ans Service: 360-715-2467 http://www.linkedin.com/in/richsmrcina Catch the WAVV! http://www.wavv.org WAVV 2009 - Orlando, FL - May 15-19, 2009
Re: Adding Slots for CP volumes in the System Config file
OK - to be a really good Sys Prog you would do both! If your System Config had been updated you would really need to know that before you do 'CP define anything' munson Kris Buelens kris.buel...@gmail.com Sent by: The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU 02/11/2009 09:26 AM Please respond to The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU To IBMVM@LISTSERV.UARK.EDU cc Subject Re: Adding Slots for CP volumes in the System Config file 2009/2/11 Bill Munson william.mun...@bbh.com: check your System Config and see what your next reserved slot is: enter - DEF CPOWN SLOT nnn volid No, to find the next reserved slot, issue CP Q CPOWNED (your SYSTEM CONFIG may already have been updated to be prepare extra slots for the next IPL) -- Kris Buelens, IBM Belgium, VM customer support *** IMPORTANT NOTE* The opinions expressed in this message and/or any attachments are those of the author and not necessarily those of Brown Brothers Harriman Co., its subsidiaries and affiliates (BBH). There is no guarantee that this message is either private or confidential, and it may have been altered by unauthorized sources without your or our knowledge. Nothing in the message is capable or intended to create any legally binding obligations on either party and it is not intended to provide legal advice. BBH accepts no responsibility for loss or damage from its use, including damage from virus.
Re: DFDSS Dump VM formatted volumes
Alan, THANX! In our user direct we place a holder on every volume from 0 1 so no overlay happens. Learned that from this fabulous list and just ass/u/me/d it was standard. Had I read this message to begin with correctly I would've understood that the individual was looking for a how to with DFDSS, not a why overall didn't it work which is why I asked if the volume was formatted. We had a guy here get a new vol, which had ickdsf run against it from z/OS, did the cpfmtxa label only, then filled it with our new experimental sles 10 sp2 shared root set up. z/OS failed to back it up or even recognize it. That's when we tried the format from 0 1 and it worked for us in that z/OS using FDR could then back it up. At 08:35 AM 2/11/2009, you wrote: On Tuesday, 02/10/2009 at 02:18 EST, Brian France b...@psu.edu wrote: We use FDR here. Run CPFMTXA to put an index vtoc on the vol at 0 that z/OS can see. FDR then just dumps the entire volume. Once, we did not do CPFMTXA and z/OS could not handle the volume. Had to run CPFMTXA on the 0 - 1 cyls to put that index vtoc out there. Um, not all volumes have a VTOC on cyl 0. A guest can have cyl 0 and it is not *required* to have a VTOC. If you write one, you may well overlay user data. Of course, if there is no VTOC, the VTOC pointer will be blank (if it is a VOL1 label) or, more likely, it will not be VOL1. FDR/DFDSS need to handle these cases. There's a reason that volume labels follow a set of standards! :-) Alan Altmark z/VM Development IBM Endicott Brian W. France Systems Administrator (Mainframe) Pennsylvania State University Administrative Information Services - Infrastructure/SYSARC Rm 25 Shields Bldg., University Park, Pa. 16802 814-863-4739 b...@psu.edu To make an apple pie from scratch, you must first invent the universe. Carl Sagan
Re: Adding Slots for CP volumes in the System Config file
On Wednesday, 02/11/2009, Alan Altmark wrote: CP_Owned Slot 256 RESERVED Finger check! Make that CP_Owned Slot 255 RESERVED (255, not 256) Alan Altmark z/VM Development IBM Endicott
LPR printing
Hello all, We're trying to use the LPR command from a z/VM 5.4 system to print to a windows print server. The problem we're having is we'd like the print file to be identified with a user different from the logon user. Is there some kind of option on the LPR command or global variable to achieve this? Thanks for your help. Mary Zervos VM Systems Programmer Binghamton University
Setting DIRM NEEDPASS NO in a LOGONBY user
I'm installing z/VM 5.4 with Dirmaint and RACF (and this time following the book as opposed to my own methods). I did copy the CONFIGRC SAMPDVH as DATADVH and DIRMAINT sees it. So, it should have all RACF enablements. MAINT is defined as a LOGONBY user and is logged on BY BUELENSC. When I issue DIRM NEEDPASS NO in MAINT, DIRMAINT prompts me for MAINT's password: - I'd say it should prompt for BUELENSC's password (I am not supposed to know MAINT's password when using LOGONBY) - So I enter BUELENSC's password and RACF rejects it. Seems that the query DIRMAINT passes to RACF indeed wants indeed an authentication as MAINT: OPERATOR gets ICH301I MAXIMUM PASSWORD ATTEMPTS BY SPECIAL USER MAINT Is this supposed to work? -- Kris Buelens, IBM Belgium, VM customer support
Re: LPR printing
I don't see anything in the help that looks like you could use. Sorry, no manuals today. -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mary Zervos Sent: Wednesday, February 11, 2009 11:38 AM To: IBMVM@LISTSERV.UARK.EDU Subject: LPR printing Hello all, We're trying to use the LPR command from a z/VM 5.4 system to print to a windows print server. The problem we're having is we'd like the print file to be identified with a user different from the logon user. Is there some kind of option on the LPR command or global variable to achieve this? Thanks for your help. Mary Zervos VM Systems Programmer Binghamton University Confidentiality Note: This e-mail, including any attachment to it, may contain material that is confidential, proprietary, privileged and/or Protected Health Information, within the meaning of the regulations under the Health Insurance Portability Accountability Act as amended. If it is not clear that you are the intended recipient, you are hereby notified that you have received this transmittal in error, and any review, dissemination, distribution or copying of this e-mail, including any attachment to it, is strictly prohibited. If you have received this e-mail in error, please immediately return it to the sender and delete it from your system. Thank you.
Re: Paging
On Tue, 10 Feb 2009 09:04:51 -0500, Martin, Terry R. (CMS/CTR) (CTR) terry.mar...@cms.hhs.gov wrote: ... 2) I believe that some of the paging slots are old data in other words the pages are not going away after a task is complete how can I research this. The Linux guests have not been recycled but I thought if they had allocated the slots that after a task within the Linux guest completed that the slots would be reclaimed. ... That's not necessarily true. When a Linux task completes, Linux does not necessarily inform CP that the link between Linux virtual and Linux real is broken and that any saved contents of the Linux real page can be discarde d. Even with CMM or CMMA enabled, Linux is not obligated to inform CP of ev ery page transition, and even when it does, CP may not notice a page is in a state where old contents (backed on CP paging DASD) can be discarded befo re Linux reuses it for some new mapping.
Re: Paging
On Tue, 10 Feb 2009 09:46:12 -0600, Brian Nielsen bniel...@sco.idaho.gov wrote: To answer your question #2: Once a guest has a slot on a CP paging devic e it will be there essentially for the life of the guest, barring somethin g like a DEF STOR. It doesn't look like the CMMA stuff extends to freeing paging slots when a guest discards pages. Brian Nielsen This isn't typically true, either. If a page on DASD is brought back in to storage (either because it was referenced by the guest, or part of a pagi ng block where any page in the block was referenced by the guest), the old paging slot from which the page was read will typically be released (free d). The only cases where the old slot would be retained is if the page was never brought in again, or where it was brought in as a non-faulted page as part of a paging block, and then never again referenced or changed (relatively unlikely). CMMA action causing a page to revert to the logically zeros state would also typically release any paging slot associated with the old page contents. There will typically be some numb er of pages, however, that are referenced only at guest startup or perhaps a t very infrequent guest state transitions, and such pages will tend to rema in in place on paging space for long periods of time. - Bill Holder, z/VM Development, IBM Endicott
Re: Paging
Some responses point by point, inline: On Tue, 10 Feb 2009 16:15:35 +0100, Kris Buelens kris.buel...@gmail.com wrote: As for the selection of good old data to be thrown out by CP: - Linux can tell CP that it no longer needs certain storage pages using a diagnose code. If it does ??? This would be Diagnose 10, the release function, as used by CMM (aka CMM1), and other so-called balooning mods/drivers. If Linux releases a range of pages using Diagnose 10, the paging space backing slots are free . - CRM 2 is a Linux/CP co-operative feature by which CP would know what kind of data resides in which Linux pages. For example: if CP knows a page is used to cache disk data, it doesn't need to page it out, Linux can read it back in from its disks. This would be CMMA, aka CMM2. When Linux puts a page in any non-stable state, CP has the opportunity to see that state and revert the page to the logically zeros state, which would trigger an asynchronous discard of a ny paging slot holding the old contents. Of course, CP would have to happen to look at the page in just the right window to make that transition (and depending on which non-stable state Linux is using, CP might have to hono r the Linux change (dirty) bit and preserve the contents and revert the p age to stable state). - Apart from that, CP's selection of candidates to page out from central storage is not as clever is in z/OS: it only uses the last reference bit. That is why a z/VM installation would be configured with some amount of expanded storage, because there is a timestamp for each expanded storage page that allows CP to select old pages for pageout. -- Kris Buelens, IBM Belgium, VM customer support Not exactly true - CP's page selection criteria does not rely simply on t he most recent reference state. Our reference pattern management scheme is actually quite a bit more sophisticated than the ones previously and currently used by z/OS in that we maintain a user local approximate LRU ordering of user pages based on user reference patterns over time, via th e User Frame Owned list of FRMTEs chained out of the VMDBK, and the Reorder process. It's the ordering of the page frames represented on this list, as much as it is the most recent reference state (all compared to other fact ors such as demand, working set, RESERVED settings, locked pages, etc.), that drive page selection criteria (and actually, in recent releases, we have reference bit management that is actually several generations of referenc e bit history deep - for example, referenced now AND referenced previous ly have priority over either referenced now but not referenced previously and not referenced now but referenced previously pages). More than anyone ever wanted to know, I'm sure. ;-) - Bill Holder, z/VM Development, IBM Endicott
Re: Paging
On Tue, 10 Feb 2009 13:21:35 -0600, Marcy Cortes marcy.d.cor...@wellsfargo.com wrote: We've seen this messages on a new system that we build that didn't have enough page space (yet). You probably need some more paging volumes - add up the sum of all the virtual machines and multiple by 2 and add *at least* that much space, more if you are using vdisk for swap.Try to keep the % full to less than 40. (that rule of thumb may vary depending on who you ask). Issue Q SRM and let us know what you have for those settings. Marcy I believe the current rule of thumb recommendation is to add up all of the sizes of the virtual machines which will be logged on at once, then add i n all the sizes of all of the vdisks which will be defined by logged on use rs, double that, and paging DASD space should be at least that large. The po int is not only to ensure there's enough paging space to hold the entire workload, but to also leave enough breathing room in terms of contiguou s available sets of paging slots (think entire tracks or more) to allow the block paging algorithms to work effeciently. - Bill Holder, z/VM Development, IBM Endicott
Re: Paging
On Tue, 10 Feb 2009 15:25:58 -0600, Dave Jones d...@vsoft-software.com wrote: Hi, Terry. Martin, Terry R. (CMS/CTR) (CTR) wrote: Hi [snp] q alloc page EXTENT EXTENT TOTAL PAGES HIGH% VOLID RDEV STARTEND PAGES IN USE PAGE USED -- -- -- -- -- -- 530PAG 5104 1 3338 600840 301180 594838 50% VP517A 517A 1 3338 600840 338482 600840 56% VP517B 517B 1 3338 600840 334685 600838 55% VP5198 5198 1 3338 600840 337162 600839 56% VP5199 5199 1 3338 600840 333914 600840 55% VP5109 5109 0 3338 601020 301240 598846 50% VP51A0 51A0 1 3338 600840 75804 76125 12% VP51A1 51A1 1 3338 600840 76068 76734 12% -- -- SUMMARY4694K 2049K 43% USABLE 4694K 2049K 43% You have noticed, I hope, that for volume VP5109, the paging area starts on cylinder 0, and not cylinder 1? Generally, I prefer to leave cylinder 0 for CP's exclusive use. -- DJ V/Soft z/VM and mainframe Linux expertise, training, consulting, and software development www.vsoft-software.com = Having cylinder 0 allocated for paging space is not a problem (as long as it's properly formatted). The only reason we recommend not to do it is t o avoid any confusion for the one instance where cylinder 0 would be a prob lem (and that is tdisk). Having cylinder 0 allocated for paging is not contributing to any of the observed symptoms (if it was properly formatte d first). - Bill Holder, z/VM Development, IBM Endicott
Re: Setting DIRM NEEDPASS NO in a LOGONBY user
The DIRMAINT install can be, or rather IS, a real PITA. Make sure that in your CONFIG* DATADVH you have replaced ESM_PASSWORD_AUTHENTICATION_EXIT= with DVHXPA EXEC rather than the older DVHDA0. Also in 140CMDS DATADVH and 150CMDS DATADVH, be sure to have column 35 set to N. AUTHFOR CONTROL needs to be set up as well on the DIRMAINT 1DF disk. I'm pretty sure that those are not the only gotcha's but they are what I have in my notes for going to 5.4. It's hard to believe that a product can have evolved with so many related and interdependent control files on different disks. I don't think that DIRMAINT was planned. It just sort of happened and I've voiced that opinion before here on the list and to various people in Endicott. Jim Kris Buelens wrote: I'm installing z/VM 5.4 with Dirmaint and RACF (and this time "following the book" as opposed to my own methods). I did copy the CONFIGRC SAMPDVH as DATADVH and DIRMAINT sees it. So, it should have all RACF enablements. MAINT is defined as a LOGONBY user and is logged on BY BUELENSC. When I issue DIRM NEEDPASS NO in MAINT, DIRMAINT prompts me for MAINT's password: - I'd say it should prompt for BUELENSC's password (I am not supposed to know MAINT's password when using LOGONBY) - So I enter BUELENSC's password and RACF rejects it. Seems that the query DIRMAINT passes to RACF indeed wants indeed an authentication as MAINT: OPERATOR gets ICH301I MAXIMUM PASSWORD ATTEMPTS BY SPECIAL USER MAINT Is this supposed to work? -- Jim Bohnsack Cornell University (972) 596-6377 home/office (972) 342-5823 cell jab...@cornell.edu
MDC size impacted after migration to z/VM 5.4
Is there anything in the transition between z/VM 5.3 SLU 0702 and z/VM 5. 4 SLU 0801 that would negatively impact MDC's use of real storage in favor of guest storage? I noticed in a recent ESAMDC report that the average size of MDC had plummeted from what it normally has been. Looking back through my historical data I see that it happened on the day and time that I migrate d from z/VM 5.3 to z/VM 5.4 (11/30/2008). MDC is in real storage only, non e in XSTORE. All MDCACHE parameters are the same as is the storage/xstore for the LPAR and vstor for the Linux guests. The MDC objective size has not changed in the reports and are way above the average MDC size. Page rates are still typically at or near zero, but the reported MDC Steals/se c has gone from near zero to the 40-70 range with prolonged intervals of 20 0- 300 and some as high as 700/sec. The ESAUSR2 report shows total resident pages for guests has increased by about the same amount as MDC storage has decreased, and it seems to be spread out across all guests, which are mostly SUSE Linux. The number of locked pages is about the same. The number of VDISK pages in real storag e is also about the same. The page rate to/from xstor is way down, which makes sense since the guests have more pages resident in real storage. I'm just not sure why C P is now favoring guest storage more at the expense of MDC than it used to. It doesn't appear to be an IPL related phenomenon, as the data across a prior IPL of z/VM 5.3 shows consistent behavior. If it's not a z/VM release related issue what else should I look at/for? Brian Nielsen
Re: LPR printing
I don't see where we can override the logon user id, but the JOB option of LPR can be used to specify a unique identifier for the printed file. Works here for me. Help file says up to 99 characters are allowed. Regards, Rick Giz r...@vsoftsys.com 770-781-3206 -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mary Zervos Sent: Wednesday, February 11, 2009 11:38 AM To: IBMVM@LISTSERV.UARK.EDU Subject: LPR printing Hello all, We're trying to use the LPR command from a z/VM 5.4 system to print to a windows print server. The problem we're having is we'd like the print file to be identified with a user different from the logon user. Is there some kind of option on the LPR command or global variable to achieve this? Thanks for your help. Mary Zervos VM Systems Programmer Binghamton University Confidentiality Note: This e-mail, including any attachment to it, may contain material that is confidential, proprietary, privileged and/or Protected Health Information, within the meaning of the regulations under the Health Insurance Portability Accountability Act as amended. If it is not clear that you are the intended recipient, you are hereby notified that you have received this transmittal in error, and any review, dissemination, distribution or copying of this e-mail, including any attachment to it, is strictly prohibited. If you have received this e-mail in error, please immediately return it to the sender and delete it from your system. Thank you.
Re: Paging
Just a few general comments: Paging space becoming full and paging errors are two different problems t hat manifest differently (though the latter can certainly contribute to the former). Inadequate paging space will not lead to paging errors being reported. If paging space becomes full, paging will overflow to spool space, and messages 401 (90% full) and 400 (100% full) will have been issued for pag ing space. If spool space also becomes full, those messages will also be iss ued for spool space, and a PGT004 hard abend will likely result. If paging errors occur, there should be EREP messages. Message 0415 (Si x continuous paging errors...) will only be issued if 6 paging IO requests in a row to a single volume all result in failures. This is really not like ly to be a hardware problem with modern highly cached virtual storage DASD systems like Shark and such. These errors almost always occur on write requests, as one slot is found to be bad (unusable), and the algorithm bumps to the next available slot and tries it in turn. As others have mentioned, it's almost always because a contiguous region of paging space was either never formatted completely, or have since been overlaid by something else (such as a minidisk). If a large enough area of paging sp ace is not correctly formatted, this can result in a PGT004 or FRF002 (or les s likely, SXP004) hard abend outage as CP finds no usable paging space to write to, and storage starts filling up with queued 0415 and EREP message s. In my experience, such paging errors are overwhelmingly caused by lack of (or improper) formatting, with minidisk overlays being a distant second, and actual disk hardware problems a very far distant third. - Bill Holder, z/VM Development, IBM Endicott
Re: LPR printing
Maybe the use of DIAG D4, CP's alternate user facility. It was created for batch jobs: user SUBMITTER submits a job the job is sent to server BATCHMONITOR server BATCHMONITOR selects a free WORKER user server BATCHMONITOR uses DIAG D4 to set WORKER's alternate user to SUBMITTER user WORKER executes the job. == all spool files created created by WORKER get SUBMITTER as spool file origin. If you have got a server that issues the LPR command, and if you want to give that server the required CP class to use DIAG D4, it may be a possibity. But I think you must use LPR parameters so that the prints are sent to RSCS, because without RSCS, LPR doesn't create a spoolfile. To try it out: get my RxServer package from the download lib, it includes a DIAGD4 MODULE. Logon to a user with the required CP class (e.g. MAINT) Issue DIAGD4 MAINT altuser Use your LPR command Issue DIAGD4 MAINT END If RACF is installed, MAINT must get a RACF PERMIT altuser CLASS(VMBATCH) ID(MAINT) 2009/2/11 Wakser, David david.wak...@infocrossing.com: I don't see anything in the help that looks like you could use. Sorry, no manuals today. -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mary Zervos Sent: Wednesday, February 11, 2009 11:38 AM To: IBMVM@LISTSERV.UARK.EDU Subject: LPR printing Hello all, We're trying to use the LPR command from a z/VM 5.4 system to print to a windows print server. The problem we're having is we'd like the print file to be identified with a user different from the logon user. Is there some kind of option on the LPR command or global variable to achieve this? Thanks for your help. Mary Zervos VM Systems Programmer Binghamton University Confidentiality Note: This e-mail, including any attachment to it, may contain material that is confidential, proprietary, privileged and/or Protected Health Information, within the meaning of the regulations under the Health Insurance Portability Accountability Act as amended. If it is not clear that you are the intended recipient, you are hereby notified that you have received this transmittal in error, and any review, dissemination, distribution or copying of this e-mail, including any attachment to it, is strictly prohibited. If you have received this e-mail in error, please immediately return it to the sender and delete it from your system. Thank you. -- Kris Buelens, IBM Belgium, VM customer support
Re: Setting DIRM NEEDPASS NO in a LOGONBY user
VM:Secure would also prompt for MAINT's password, using the logic that even if you had LOGONBY to a user ID, that wouldn't grant you the capability to change the directory entry for that ID. Bob Bolch - I'd say it should prompt for BUELENSC's password (I am not supposed to know MAINT's password when using LOGONBY)
Re: Paging
On Wed, Feb 11, 2009 at 6:11 PM, Bill Holder hold...@us.ibm.com wrote: That's not necessarily true. When a Linux task completes, Linux does not necessarily inform CP that the link between Linux virtual and Linux real is broken and that any saved contents of the Linux real page can be discarded. Yes, I believe it is rather risky to make such statements only based on reading the glossies and filling in the blanks. It works better to do measurements to confirm the assumptions. For the average Linux server, most of the virtual machine is LRU managed memory (either page cache, JVM heap, DB buffers, SGA, etc). Once you start paging in z/VM, then *all* that memory will ultimately land on z/VM paging space. This is why we say that typically for each GB of Linux virtual memory and in-use swap VDISK, you must add 2 GB of z/VM paging space. Only exception is when you don't page ever in z/VM (only very few shops can afford that). And in some cases it can even be worse. Because the paging cleanup in z/VM is not immediate, it may take a while before the slot is freed. We've even seen a virtual machine take twice as much pages on DASD than it has paged out... Even with CMM or CMMA enabled, Linux is not obligated to inform CP of every page transition, and even when it does, CP may not notice a page is in a state where old contents (backed on CP paging DASD) can be discarded before Linux reuses it for some new mapping. As I stated above, you need measurements to confirm assumptions before you share them. Since there is no instrumentation for CMMA, I am reluctant to comment :-) But when my guess is as good as yours, I think it is very likely that for Linux LRU managed memory CP would not have a clue when the page went through a cycle of in-use, free, in-use. So CP will continue to hold onto the previously paged out content (until we page it out again). Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/
Re: Adding Slots for CP volumes in the System Config file
Hi Thanks for the information here. I know how to check for free SLOTS my main question was if I could add new SLOTS dynamically if they were all used up. Thank You, Terry Martin Lockheed Martin - Information Technology z/OS z/VM Systems - Performance and Tuning Cell - 443 632-4191 Work - 410 786-0386 terry.mar...@cms.hhs.gov -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Kris Buelens Sent: Wednesday, February 11, 2009 9:27 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Adding Slots for CP volumes in the System Config file 2009/2/11 Bill Munson william.mun...@bbh.com: check your System Config and see what your next reserved slot is: enter - DEF CPOWN SLOT nnn volid No, to find the next reserved slot, issue CP Q CPOWNED (your SYSTEM CONFIG may already have been updated to be prepare extra slots for the next IPL) -- Kris Buelens, IBM Belgium, VM customer support
Re: Paging
In my experience, such paging errors are overwhelmingly caused by lack of (or improper) formatting, with minidisk overlays being a distant second, and actual disk hardware problems a very far distant third. - Bill Holder, z/VM Development, IBM Endicott ICKDSF EXAMINE will show exactly which cylinders aren't properly formatted, if that's indeed the problem. As suggested previously, the volume should be DRAINed and then the unformatted cylinders detected by EXAMINE can be (very carefully!) formatted using the appropriate CPVOL FORMAT RANGE(x,y) commands without taking down your system. Or, for the faint of heart, flag the offending volume DRAINed in SYSTEM CONFIG, re-IPL, format it, and turn it back on. I also make a point to copy ICKSADSF MODULE to my CF1 disk so it's available for this and other purposes in a stand-alone environment. Mark Wheeler 3M Company
Re: Adding Slots for CP volumes in the System Config file
Hi Alan, So that I understand what you are saying, I would add the CP-OWNED SLOT 255 RESERVED where in the SYS CONFIG file? And when this is added does it mean that let's say my last RESERVED SLOT in the SYS CONFIG file was 10 and I added the 255 SLOT statement after this and I now wanted to add a CP-OWNED volume dynamically I would do a CP OWNED command using SLOT 11 and so on. I then assume I would go into the SYS CONFIG file and add a CP-OWNED SLOT statement (CP_OWNED SLOT 11) before the CP_OWNED SLOT 255? I hope this makes sense! Thank You, Terry Martin Lockheed Martin - Information Technology z/OS z/VM Systems - Performance and Tuning Cell - 443 632-4191 Work - 410 786-0386 terry.mar...@cms.hhs.gov -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Alan Altmark Sent: Wednesday, February 11, 2009 11:20 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Adding Slots for CP volumes in the System Config file On Wednesday, 02/11/2009, Alan Altmark wrote: CP_Owned Slot 256 RESERVED Finger check! Make that CP_Owned Slot 255 RESERVED (255, not 256) Alan Altmark z/VM Development IBM Endicott
Re: MDC size impacted after migration to z/VM 5.4
On Wed, 11 Feb 2009 11:51:04 -0600, Brian Nielsen bniel...@sco.idaho.gov wrote: Is there anything in the transition between z/VM 5.3 SLU 0702 and z/VM 5 .4 SLU 0801 that would negatively impact MDC's use of real storage in favor of guest storage? I noticed in a recent ESAMDC report that the average size of MDC had plummeted from what it normally has been. Looking back through my historical data I see that it happened on the day and time that I migrat ed from z/VM 5.3 to z/VM 5.4 (11/30/2008). MDC is in real storage only, no ne in XSTORE. All MDCACHE parameters are the same as is the storage/xstore for the LPAR and vstor for the Linux guests. The MDC objective size has not changed in the reports and are way above the average MDC size. Page rates are still typically at or near zero, but the reported MDC Steals/s ec has gone from near zero to the 40-70 range with prolonged intervals of 2 00- 300 and some as high as 700/sec. The ESAUSR2 report shows total resident pages for guests has increased b y about the same amount as MDC storage has decreased, and it seems to be spread out across all guests, which are mostly SUSE Linux. The number o f locked pages is about the same. The number of VDISK pages in real stora ge is also about the same. The page rate to/from xstor is way down, which makes sense since the guests have more pages resident in real storage. I'm just not sure why CP is now favoring guest storage more at the expense of MDC than it used to . It doesn't appear to be an IPL related phenomenon, as the data across a prior IPL of z/VM 5.3 shows consistent behavior. If it's not a z/VM release related issue what else should I look at/for? Brian Nielsen = === We've been tracking some issues with unexpected MDC arbiter decisions tha t this may well be an example of (it has been observed that seemingly unrelated storage changes elsewhere can affect MDC arbiter behavior due t o the way the arbiter algorithm works), but there were also some APARs (VM64082 and VM64510 come to mind) that could have caused some changes, I 'll have to check in to the contents of those RSUs and get back to you later. - Bill Holder, z/VM Development, IBM Endicott
Re: Paging
On Wed, 11 Feb 2009 19:02:14 +0100, Rob van der Heij rvdh...@velocitysoftware.com wrote: ...(deleted for brevity)... It's certainly a fair point that a complete picture is formed only with b oth actual measurements of real world representative workloads as well as t he more theoretical knowledge of how the code actually works internally. As the development team leader and design owner of the portion of CP involve d, I was speaking primarily from the latter perspective, I hope that was generally understood. I believe that what I stated was correct, however: although CP certainly does not hold on to old paging slots as tenacious ly as some folks believe, Linux is by no means obligated to inform CP every time it discards or remaps page contents, which limits CP's ability to fr ee the old paging slots. There's a lot of it depends in there, between th e code algorithms and the observed behaviors. My statements were (are) generally not based on assumptions, but rather o n how the code actually works. I don't need measurements to explain how th e code works. Of course, for any real world workload, how the design manifests in terms of externally visible behaviors is definitely the sort of your mileage may vary case where the measuring approach of course has immense value. - Bill Holder, z/VM Development, IBM Endicott
VM Live migration
I'm not sure this hasn't been asked (and subsequently answered) before, but couldn't find anything in the archives pertaining to this (possibly due to my lack of correctly using the search tool !) Anyway... Does anyone know if z/VM will eventually support ... - A Possibility to save a virtual machine status for subsequent restart - SAVESYS doesn't really cut the bill since it doesn't save I/O status. - And eventually the possibility to perform a 'hot' move of a virtual machine from a z/VM system to another (a la VMotion if you get my drift). --Ivan
Re: Paging
On Wed, Feb 11, 2009 at 7:56 PM, Bill Holder hold...@us.ibm.com wrote: My statements were (are) generally not based on assumptions, but rather on how the code actually works. I don't need measurements to explain how the Most certainly Bill. I was catching up with the thread and incorrectly put my comments on your post cutting away the wrong section. I was aiming at the unfounded assumptions about CMM and CMMA in this area. I do realize your comments are based on knowing the code, which should be enough (apart from some surprises when we learn what Linux does). My apologies if I spoiled your afternoon. I owe you a very adult beverage next time we meet. -Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/
Re: MDC size impacted after migration to z/VM 5.4
On Wed, 11 Feb 2009 12:41:04 -0600, Bill Holder hold...@us.ibm.com wrot e: We've been tracking some issues with unexpected MDC arbiter decisions th at this may well be an example of (it has been observed that seemingly unrelated storage changes elsewhere can affect MDC arbiter behavior due to the way the arbiter algorithm works), but there were also some APARs (VM64082 and VM64510 come to mind) that could have caused some changes, I'll have to check in to the contents of those RSUs and get back to you later. - Bill Holder, z/VM Development, IBM Endicott = === Thanks. If you need any more data I will happily collect it. I won't try experimenting with changing any parameters yet, but if you're aware of any changes that might be beneficial or detrimental please let m e know. Brian Nielsen
Re: Adding Slots for CP volumes in the System Config file
On Wed, Feb 11, 2009 at 5:19 PM, Alan Altmark alan_altm...@us.ibm.com wrote: Finger check! Make that CP_Owned Slot 255 RESERVED I *love* this one, and I envy the one who came up with it... I have run into several folks who misunderstood the reserved as that you can't use it. If you put this in the default system config, then all we need is a change in Q CPOWN that will show them as FREE rather than RESERVED, and people would not need to know the stuff with reserved slots at all. Rob
Re: VM Live migration
Ivan, IBM demonstrated a Live Guest Migration research project at the San Jose SHARE. No statement was made regarding if or when it will be available, but clearly IBM is doing more than just thinking about it. Dennis O'Brien 39,585 -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Ivan Warren Sent: Wednesday, February 11, 2009 11:05 To: IBMVM@LISTSERV.UARK.EDU Subject: [IBMVM] VM Live migration I'm not sure this hasn't been asked (and subsequently answered) before, but couldn't find anything in the archives pertaining to this (possibly due to my lack of correctly using the search tool !) Anyway... Does anyone know if z/VM will eventually support ... - A Possibility to save a virtual machine status for subsequent restart - SAVESYS doesn't really cut the bill since it doesn't save I/O status. - And eventually the possibility to perform a 'hot' move of a virtual machine from a z/VM system to another (a la VMotion if you get my drift). --Ivan
Re: VM Live migration
There has been a demo of this technology at SHARE. See the presentation archive on linux390.org. Romney White discusses the technology. It may even come to a release of z/VM in the not too distant future... :) Ivan Warren wrote: I'm not sure this hasn't been asked (and subsequently answered) before, but couldn't find anything in the archives pertaining to this (possibly due to my lack of correctly using the search tool !) Anyway... Does anyone know if z/VM will eventually support ... - A Possibility to save a virtual machine status for subsequent restart - SAVESYS doesn't really cut the bill since it doesn't save I/O status. - And eventually the possibility to perform a 'hot' move of a virtual machine from a z/VM system to another (a la VMotion if you get my drift). --Ivan -- Rich Smrcina VM Assist, Inc. Phone: 414-491-6001 Ans Service: 360-715-2467 http://www.linkedin.com/in/richsmrcina Catch the WAVV! http://www.wavv.org WAVV 2009 - Orlando, FL - May 15-19, 2009
Re: Paging
Thanks Dennis! Thank You, Terry Martin Lockheed Martin - Information Technology z/OS z/VM Systems - Performance and Tuning Cell - 443 632-4191 Work - 410 786-0386 terry.mar...@cms.hhs.gov From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of O'Brien, Dennis L Sent: Wednesday, February 11, 2009 12:28 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Paging Terry, You should definitely DRAIN the volume until you can fix it. The CP DRAIN command will take care of that until you IPL Instead of linking the volume and changing the label so that the volume won't be used after IPL, I find it easier to drain the volume in SYSTEM CONFIG. Add the lines DrainVolidVP51A0 PAGE DrainVolidVP51A1 PAGE to SYSTEM CONFIG. After you IPL and re-format the volumes with CPFMTXA, take those lines out and CP START the volumes. There's nothing wrong with Mike's method. I just think mine is easier. Use whichever you like. Dennis O'Brien 39,585 From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mike Walter Sent: Tuesday, February 10, 2009 20:33 To: IBMVM@LISTSERV.UARK.EDU Subject: Re: [IBMVM] Paging If there are no overlapsn then all I can think of is a real hardware error (unlikely, right?), or the repeated warnings about not having formatted EVERY CP-allocated cylinder (usually the first or last cylinder in an allocation). Yes, DRAIN the volume. CP won't right new pages to it. If you CP RESET or IPL virtual servers with pages on it, they will not be paged in. You can even allocate a minidisk on cylinder zero (personally, I'd allocate the full pack), link to that mdisk R/W, run CPFMTXA on.it ONLY to re-label it to some temporary volser (e.g. vmxx01). Since it is already online, CP won't see the label change untl the next time it comes online. Since a page volume with allocated cylinders can't be taken offline on a running system, it won't be used by the system at the next IPL. Let the system come up (presuming that by then it will have more page volumes), and you can run CPFMTXA on it at your leisure. Be 100% certain at that to format the whole volume from cyl 0 to end, and then alloc Cyl 0 as perm and 1 to end as page, also re-labeling it as it's desired page volser. Spool the console START and save it so you have proof later. You can then dynamically bring it online and CP START it for paging. Mike Walter Hewitt Associates From: Martin, Terry R. (CMS/CTR) (CTR) [terry.mar...@cms.hhs.gov] Sent: 02/10/2009 10:53 PM EST To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Paging Hi I have searched high and low and cannot for the life of me see anything that would have caused the page errors. These packs are not being accessed by any other user of LPAR and from all indications no cylinders have been overwritten. These two packs were bran new and formatted for the first time with CPFMTXA as page volumes. I guess my question is should I put a DRAIN on them before something tries to use them again and once/if drained remove them and re-init them and add them back? I am assuming that I will continue to see the page errors if these page packs are still being used correct? To sum this all up the page slots that are in use in my case adds up to about 39% of all the pages in use will not be reclaimed or paged in by the Linux guest until either the guest is recycled or the LPAR is IPL'ed is this a correct assumption for the most part? Now I see why so many page data sets are required for this z/Linux environment, interesting Terry From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of David Boyes Sent: Tuesday, February 10, 2009 7:04 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Paging That tells me that you allocated them correctly. The question is whether DSF actually wrote CP-compatible blocks (which are different than what minidisks use) on every cylinder. That's one of the reasons why I always add paging areas in full packs, and always run DSF on them, even if they're brand new or already been formatted by Some Other OS. From the other conversation, you may have ended up with a minidisk overlapping a paging area. In either case, you should reformat the disks in question next time you IPL and have the system down for any period (can't do it while it's up if pages have actually been written to the paging areas; CP doesn't really give you an easy way to force migration of pages off a pack if they are still referenced by something). Taking the problem volumes offline and bringing the system up to the point of having OPERATOR logged in but before AUTOLOG1 comes up would be one way to safely reformat them without going to standalone DSF. As Marcy said,
Re: LPR printing
We're trying to use the LPR command from a z/VM 5.4 system to print to a windows print server. The problem we're having is we'd like the print file to be identified with a user different from the logon user. Is there some kind of option on the LPR command or global variable to achieve this? I think you could do this if you used the RSCS LPR support (rather than directly sending it to the printer from the virtual machine). You could manipulate the tag data of the spool file from a privileged ID, then transfer it to RSCS for printing. The LPR support is part of the TCP components of RSCS you're permitted to use without license. The RSCS LPR links are more stable anyway, and don't tie up the virtual machine.
Re: VM Live migration
...and the demo was really cool! (Obviously, I'm a child of the 50's) But unless I missed something, it does not directly address your stated desire: to save a virtual machine status for subsequent restart The Live Guest Migration presentation moved guests on the fly from one CEC to another CEC. There were lots (LOTS) of restrictions regarding what circumstances would prevent a guest from being migrated. If this ever sees GA, one would expect IBM to probably work at remove as many restrictions as feasible as expeditiously as possible. The idea of saving a guest for later quick restart (kickstart, if that's not trademarked) is intriguing. Could you supply a business case wherein such a quickstart would provide real value to any/your business? Mike Walter Hewitt Associates Any opinions expressed herein are mine alone and do not necessarily represent the opinions or policies of Hewitt Associates. Rich Smrcina rsmrc...@wi.rr.com Sent by: The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU 02/11/2009 01:11 PM Please respond to The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU To IBMVM@LISTSERV.UARK.EDU cc Subject Re: VM Live migration There has been a demo of this technology at SHARE. See the presentation archive on linux390.org. Romney White discusses the technology. It may even come to a release of z/VM in the not too distant future... :) Ivan Warren wrote: I'm not sure this hasn't been asked (and subsequently answered) before, but couldn't find anything in the archives pertaining to this (possibly due to my lack of correctly using the search tool !) Anyway... Does anyone know if z/VM will eventually support ... - A Possibility to save a virtual machine status for subsequent restart - SAVESYS doesn't really cut the bill since it doesn't save I/O status. - And eventually the possibility to perform a 'hot' move of a virtual machine from a z/VM system to another (a la VMotion if you get my drift). --Ivan -- Rich Smrcina VM Assist, Inc. Phone: 414-491-6001 Ans Service: 360-715-2467 http://www.linkedin.com/in/richsmrcina Catch the WAVV! http://www.wavv.org WAVV 2009 - Orlando, FL - May 15-19, 2009 The information contained in this e-mail and any accompanying documents may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message, including any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited. All messages sent to and from this e-mail address may be monitored as permitted by applicable law and regulations to ensure compliance with our internal policies and to protect our business. E-mails are not secure and cannot be guaranteed to be error free as they can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by e-mail.
Re: Adding Slots for CP volumes in the System Config file
So that I understand what you are saying, I would add the CP-OWNED SLOT 255 RESERVED where in the SYS CONFIG file? And when this is added does it mean that let's say my last RESERVED SLOT in the SYS CONFIG file was 10 and I added the 255 SLOT statement after this and I now wanted to add a CP-OWNED volume dynamically I would do a CP OWNED command using SLOT 11 and so on. I then assume I would go into the SYS CONFIG file and add a CP-OWNED SLOT statement (CP_OWNED SLOT 11) before the CP_OWNED SLOT 255? The location and order of the CP_Owned statements doesn't matter. They don't even have to be listed in order of the slot numbers. Having said that, for readability, maintainability, and to keep us all sane, it is a good practice to specify them all together and in slot numnber order. Specifying SLOT 255 RESERVED will mark all of the slots following your last defined (real volume) slot as Reserved. CP_Owned Definitions in SYSTEM CONFIG: CP_Owned Slot 1 JF1RES Own CP_Owned Slot 2 SPOOL1 Share CP_Owned Slot 3 MDSP1 Share CP_Owned Slot 4 DUMP1 Share CP_Owned Slot 5 SPOOL0 Own CP_Owned Slot 6 MDSP0 Own CP_Owned Slot 7 DUMP0 Own CP_Owned Slot 8 TEMP00 Own CP_Owned Slot 9 TEMP01 Own CP_Owned Slot 10 TEMP02 Own CP_Owned Slot 255 Reserved QUERY CPOWNED result when system is IPLed (all of the removed slots will appear; I removed them to keep this readable: q cpowned Slot Vol-ID Rdev Type Status 1 JF1RES 0A40 OwnOnline and attached 2 SPOOL1 0781 Share Online and attached 3 MDSP1 0881 Share Online and attached 4 DUMP1 Share Offline 5 SPOOL0 0780 OwnOnline and attached 6 MDSP0 0880 OwnOnline and attached 7 DUMP0 OwnOffline 8 TEMP00 OwnOffline 9 TEMP01 OwnOffline 10 TEMP02 0785 OwnOnline and attached 11 -- - Reserved 12 -- - Reserved 13 -- - Reserved 14 -- - Reserved 15 -- - Reserved . .(slots 16-249 removed) . 250 -- - Reserved 251 -- - Reserved 252 -- - Reserved 253 -- - Reserved 254 -- - Reserved 255 -- - Reserved Ready; John Franciscovich z/VM Development
Re: LPR printing
On Wednesday, 02/11/2009 at 11:39 EST, Mary Zervos zer...@binghamton.edu wrote: We're trying to use the LPR command from a z/VM 5.4 system to print to a windows print server. The problem we're having is we'd like the print file to be identified with a user different from the logon user. Is there some kind of option on the LPR command or global variable to achieve this? There are no built-in options to override the user name. However, LPR gets your user ID by issuing the IDENTIFY (LIFO command and expects to find userid AT nodeid as the first 3 tokens. If you're familiar with building nucleus extensions and the NUCXLOAD command, you can build your own IDENTIFY program that returns whatever you want. If you have the REXX compiler, this is exceptionally easy to do. If you use RSCS for printing, the user ID is taken from the spool file origin. If you want ALL files sent via that RSCS LPR link to appear to be from one specific user, then you can code USERNAME=userid in the LPRXONE or LPRXPSE CONFIG file. See the RSCS Exit Customization book for details. Alan Altmark z/VM Development IBM Endicott
Re: Paging
On 2/11/09 2:07 PM, Martin, Terry R. (CMS/CTR) (CTR) terry.mar...@cms.hhs.gov wrote: Hi Thanks to all for your thoughtful input. I think I see the issue now and it does appear to be a formatting problem. When I formatted the pack using CPFMTXA I did the following: When I was prompted to do the following I replied 0 0: I believe it should have been 0 END. Ding ding ding! Yep, that's EXACTLY it.
Re: Paging
On Wed, 11 Feb 2009 14:07:18 -0500, Martin, Terry R. (CMS/CTR) (CTR) terry.mar...@cms.hhs.gov wrote: ... Does this sound like a logical explanation? ... Yes, I think that's the explanation. Unless the previous format of the remaining cylinders just coincidentally happened to be compatible, it's n ot likely that any pages got written out successfully to those volumes. The one exception might be that one volume that Dave Jones noticed had cylind er 0 allocated as page - if that was formatted the same way, the system might've successfully paged out up to 180 pages to it (one cylinder's worth). I'm actually somewhat surprised you didn't run into one of the other problems I mentioned (FRF002, PGT004, SXP004) with that much unformatted paging space. - Bill Holder, z/VM Development, IBM Endicott
Re: MDC size impacted after migration to z/VM 5.4
It doesn't look like either level (5.3.0 SLU 0702 or 5.4.0 SLU 0801) contains either APAR in question (VM64082 or VM64510), so unless you've applied them proactively, it sounds like we can rule them out. I think we're going to want to look into what's going on in a little more detail - it's possible it's an example of the issue I mentioned, but it's also possible that 5.4.0's decision might actually be a better overall tradeof f. - Bill Holder, z/VM Development, IBM Endicott
Copying a VMtape on zOS
Hello, I need to copy a logical tape in a VTS to another logical tape in the VTS to force the data to an export pool. I am having trouble coping the tape due to the large blocksize. The JCL manual suggests using BLKSZLIM=49280. I am using an IDCAMS repro, but get an open error complaining about blocksize. Any suggestions would be appreciated. My JCL is below. //U20445UT JOB (C110,2,000,SYS,20445,K),'SED(3A)-UTZVMCPY', // MSGCLASS=Q,CLASS=S,NOTIFY=U20445 //* - //* //* //* //STEP0001 EXEC PGM=IDCAMS //SYSPRINT DD SYSOUT=* //ZVMINDD VOL=SER=L9, //DISP=(OLD,KEEP),LABEL=(,BLP),UNIT=TAPE, //DCB=(DEN=2,RECFM=U,LRECL=X),BLKSZLIM=49280 //ZVMOUT DD DSN=ZVMTAPE.COPYOF.L9.YMD.D090209, //DISP=(NEW,CATLG,DELETE),LABEL=(,NL), //UNIT=TAPE,MGMTCLAS=MCZVM, //DCB=(DEN=2,RECFM=U,LRECL=X),BLKSZLIM=49280 //SYSINDD * REPRO INFILE(ZVMIN) OUTFILE(ZVMOUT) /* // Scott Davis IS Operating Systems Specialist III, ETS: Infrastructure/Platform Support Services OKDHS - Data Services Division Work (405) 522-1982 Fax (405) 522-6025 Pager (800) 647-7243 Pin #0924 Email scott.da...@okdhs.org
Re: Setting DIRM NEEDPASS NO in a LOGONBY user
On Wednesday, 02/11/2009 at 11:40 EST, Kris Buelens kris.buel...@gmail.com wrote: I'm installing z/VM 5.4 with Dirmaint and RACF (and this time following the book as opposed to my own methods). I did copy the CONFIGRC SAMPDVH as DATADVH and DIRMAINT sees it. So, it should have all RACF enablements. MAINT is defined as a LOGONBY user and is logged on BY BUELENSC. When I issue DIRM NEEDPASS NO in MAINT, DIRMAINT prompts me for MAINT's password: - I'd say it should prompt for BUELENSC's password (I am not supposed to know MAINT's password when using LOGONBY) - So I enter BUELENSC's password and RACF rejects it. Seems that the query DIRMAINT passes to RACF indeed wants indeed an authentication as MAINT: OPERATOR gets ICH301I MAXIMUM PASSWORD ATTEMPTS BY SPECIAL USER MAINT Is this supposed to work? I would say No. You have LOGON BY access, but that doesn't confer modify the directory permission. If MAINT is LBYONLY (in the RACF sense) then you need to make such changes from another user who is authorized to act FOR MAINT. Alan Altmark z/VM Development IBM Endicott
Re: Copying a VMtape on zOS
Can't use DITTO? I believe it will allow you to use the larger block sizes. From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Davis, Scott Sent: Wednesday, February 11, 2009 12:35 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Copying a VMtape on zOS Hello, I need to copy a logical tape in a VTS to another logical tape in the VTS to force the data to an export pool. I am having trouble coping the tape due to the large blocksize. The JCL manual suggests using BLKSZLIM=49280. I am using an IDCAMS repro, but get an open error complaining about blocksize. Any suggestions would be appreciated. My JCL is below. //U20445UT JOB (C110,2,000,SYS,20445,K),'SED(3A)-UTZVMCPY', // MSGCLASS=Q,CLASS=S,NOTIFY=U20445 //* - //* //* //* //STEP0001 EXEC PGM=IDCAMS //SYSPRINT DD SYSOUT=* //ZVMINDD VOL=SER=L9, //DISP=(OLD,KEEP),LABEL=(,BLP),UNIT=TAPE, //DCB=(DEN=2,RECFM=U,LRECL=X),BLKSZLIM=49280 //ZVMOUT DD DSN=ZVMTAPE.COPYOF.L9.YMD.D090209, //DISP=(NEW,CATLG,DELETE),LABEL=(,NL), //UNIT=TAPE,MGMTCLAS=MCZVM, //DCB=(DEN=2,RECFM=U,LRECL=X),BLKSZLIM=49280 //SYSINDD * REPRO INFILE(ZVMIN) OUTFILE(ZVMOUT) /* // Scott Davis IS Operating Systems Specialist III, ETS: Infrastructure/Platform Support Services OKDHS - Data Services Division Work (405) 522-1982 Fax (405) 522-6025 Pager (800) 647-7243 Pin #0924 Email scott.da...@okdhs.org Confidentiality Note: This e-mail, including any attachment to it, may contain material that is confidential, proprietary, privileged and/or Protected Health Information, within the meaning of the regulations under the Health Insurance Portability Accountability Act as amended. If it is not clear that you are the intended recipient, you are hereby notified that you have received this transmittal in error, and any review, dissemination, distribution or copying of this e-mail, including any attachment to it, is strictly prohibited. If you have received this e-mail in error, please immediately return it to the sender and delete it from your system. Thank you.
Re: Adding Slots for CP volumes in the System Config file
On Wednesday, 02/11/2009 at 02:32 EST, Rob van der Heij rvdh...@gmail.com wrote: On Wed, Feb 11, 2009 at 5:19 PM, Alan Altmark alan_altm...@us.ibm.com wrote: Finger check! Make that CP_Owned Slot 255 RESERVED I *love* this one, and I envy the one who came up with it... I have run into several folks who misunderstood the reserved as that you can't use it. If you put this in the default system config, then all we need is a change in Q CPOWN that will show them as FREE rather than RESERVED, and people would not need to know the stuff with reserved slots at all. FREE would be ok if we removed the requirement to RESERVE them. Otherwise the other half of the world will complain that the status of the slot shows FREE yet they defined it as RESERVED and why don't they match? Of course, it's not FREE, either. Just ask your Purchasing group. ;-) Alan Altmark z/VM Development IBM Endicott
Re: Copying a VMtape on zOS
You could use iebgener.. //COPYRTU EXEC PGM=IEBGENER //SYSPRINT DD SYSOUT=* //SYSUT1 DD DISP=SHR, //DSN=CCMW.RTU //SYSUT2 DD DISP=(,KEEP,DELETE), //UNIT=TPFTAPE, //DSN=ACP.RTU, //DATACLAS=CTAP, //DCB=*.SYSUT1 //SYSINDD DUMMY Davis, Scott scott.da...@okdh s.org To Sent by: The IBM IBMVM@LISTSERV.UARK.EDU z/VM Operating cc System ib...@listserv.u Subject ARK.EDU Copying a VMtape on zOS 02/11/2009 10:34 AM Please respond to The IBM z/VM Operating System ib...@listserv.u ARK.EDU Hello, I need to copy a logical tape in a VTS to another logical tape in the VTS to force the data to an export pool. I am having trouble coping the tape due to the large blocksize. The JCL manual suggests using BLKSZLIM=49280. I am using an IDCAMS repro, but get an open error complaining about blocksize. Any suggestions would be appreciated. My JCL is below. //U20445UT JOB (C110,2,000,SYS,20445,K),'SED(3A)-UTZVMCPY', // MSGCLASS=Q,CLASS=S,NOTIFY=U20445 //* - //* //* //* //STEP0001 EXEC PGM=IDCAMS //SYSPRINT DD SYSOUT=* //ZVMINDD VOL=SER=L9, //DISP=(OLD,KEEP),LABEL=(,BLP),UNIT=TAPE, //DCB=(DEN=2,RECFM=U,LRECL=X),BLKSZLIM=49280 //ZVMOUT DD DSN=ZVMTAPE.COPYOF.L9.YMD.D090209, //DISP=(NEW,CATLG,DELETE),LABEL=(,NL), //UNIT=TAPE,MGMTCLAS=MCZVM, //DCB=(DEN=2,RECFM=U,LRECL=X),BLKSZLIM=49280 //SYSINDD * REPRO INFILE(ZVMIN) OUTFILE(ZVMOUT) /* // Scott Davis IS Operating Systems Specialist III, ETS: Infrastructure/Platform Support Services OKDHS - Data Services Division Work (405) 522-1982 Fax (405) 522-6025 Pager (800) 647-7243 Pin #0924 Email) scott.da...@okdhs.org.
Re: MDC size impacted after migration to z/VM 5.4
On Wed, 11 Feb 2009 14:35:37 -0600, Bill Holder hold...@us.ibm.com wrot e: It doesn't look like either level (5.3.0 SLU 0702 or 5.4.0 SLU 0801) contains either APAR in question (VM64082 or VM64510), so unless you've applied them proactively, it sounds like we can rule them out. I think we're going to want to look into what's going on in a little more detail - it's possible it's an example of the issue I mentioned, but it's also possible that 5.4.0's decision might actually be a better overall tradeoff. - Bill Holder, z/VM Development, IBM Endicott I did some looking, and saw in the z/VM Performance Report under z/VM 5.4 Performance Considerations in the MDC Changes section it says that: APAR VM64082 to z/VM 5.2 and 5.3 changes the behavior of the MDC storage arbiter. Recall the arbiter's job is to determine how to proportion storage between guest frames and MDC. This APAR, rolled into the z/VM 5.4 base, is not on any z/VM 5.2 or 5.3 RSU. So VM64082 should be on my z/VM 5.4 system. I read the descriptions for both APARs and it does sound like it is my problem. I see that VM64510 is on SLU 0802, but in the meantime I may adjust my MDCACHE minimum size and/or bias values as suggested in the above referenced Performance Report section. Is there a potential that doing s o will cause problems in the other storage routine processes mentioned in the APARs? Brian Nielsen
Re: Short user description in sample CP directory
Thank you! Thank you! Thank you! The most beautiful and well written web page I ever saw. Should be required reading for everyone who ever allocates VM dasd. Alan Altmark wrote: By the way, the VTOC page is done. Please see http://www.vm.ibm.com/devpages/altmarka/vtoc.html for information about the VTOC on a CP-owned volume. Alan Altmark z/VM Development IBM Endicott -- Stephen Frazier Information Technology Unit Oklahoma Department of Corrections 3400 Martin Luther King Oklahoma City, Ok, 73111-4298 Tel.: (405) 425-2549 Fax: (405) 425-2554 Pager: (405) 690-1828 email: stevef%doc.state.ok.us
Re: MDC size impacted after migration to z/VM 5.4
On Wed, 11 Feb 2009 15:22:56 -0600, Brian Nielsen bniel...@sco.idaho.gov wrote: ... I did some looking, and saw in the z/VM Performance Report under z/VM 5. 4 Performance Considerations in the MDC Changes section it says that: APAR VM64082 to z/VM 5.2 and 5.3 changes the behavior of the MDC storag e arbiter. Recall the arbiter's job is to determine how to proportion storage between guest frames and MDC. This APAR, rolled into the z/VM 5. 4 base, is not on any z/VM 5.2 or 5.3 RSU. So VM64082 should be on my z/VM 5.4 system. I read the descriptions for both APARs and it does sound like it is my problem. I see that VM64510 is on SLU 0802, but in the meantime I may adjust my MDCACHE minimum size and/or bias values as suggested in the above referenced Performance Report section. Is there a potential that doing so will cause problems in the other storage routine processes mentioned in the APARs? Brian Nielsen = === I'm sorry I missed that, I forgot to check if VM64082 was in the 5.4.0 ba se, but that does sound right, I knew that at one point, now that I think abo ut it. You definitely do want to get and apply VM64510, then, and see how t hat affects things. In the meantime, yes, you do want to adjust your setting s. As long as you don't exceed the values you were typically seeing on 5.3. 0, that shouldn't affect other processes appreciably. - Bill Holder, z/VM Development, IBM Endicott
