Re: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory
On Sat, Nov 6, 2010 at 11:03 AM, Alan Altmark alan_altm...@us.ibm.com wrote: some really ugly stuff regarding IOCP and overloaded control unit definitions ew... You just made me throw up in my mouth a little bit... We do this sort of thing here in the lab to get around issues where two teams are forced to cohabitate on a single CEC without altering their respective I/O environments. Multiple I/O subsystems on z990 and newer machines makes this a little more tolerable than it used to be. If you absolutely must, do it with HCD or some other tool to help you get it right. Its very easy to do wrong. It is ugly and bad. I strongly recommend against it, if you have any other option. -- Jay Brenneman
Re: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory
You just made me throw up in my mouth a little bit... That is perhaps one of Chuckies favorite objectives, the little sicko! Surely Chuckie was at the keyboard when Alan was out of room... again. I'm still mulling over alternatives. But refining the I/O environment is one of the least-attractive alternatives. A SHARE and WAVV requirement would be much cleaner than anything I've seen suggested up to this point. That requirement would have to clearly state that the requirement is meant for use with grown up Operating Systems which prevent uncontrolled concurrent writes to the same DASD in an unmanaged way (i.e. supporting reserve/release and perhaps ENQ/DEQ or whatever else z/OS favors nowadays). Thanks for all the help so far. The PMR has not yielded anything better at this time. Mike Walter Aon Corporation The opinions expressed herein are mine alone, not my employer's. Robert J Brenneman bren...@gmail.com Sent by: The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU 11/08/2010 01:02 PM Please respond to The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU To IBMVM@LISTSERV.UARK.EDU cc Subject Re: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory On Sat, Nov 6, 2010 at 11:03 AM, Alan Altmark alan_altm...@us.ibm.com wrote: some really ugly stuff regarding IOCP and overloaded control unit definitions ew... You just made me throw up in my mouth a little bit... We do this sort of thing here in the lab to get around issues where two teams are forced to cohabitate on a single CEC without altering their respective I/O environments. Multiple I/O subsystems on z990 and newer machines makes this a little more tolerable than it used to be. If you absolutely must, do it with HCD or some other tool to help you get it right. Its very easy to do wrong. It is ugly and bad. I strongly recommend against it, if you have any other option. -- Jay Brenneman 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: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory
On Friday, 11/05/2010 at 12:23 EDT, Schuh, Richard rsc...@visa.com wrote: Both HDS and EMC have provided CP updates to the CCW translation tables. In fact, for 6.1 IBM has included the updates that HDS has supported for the last several releases. With those updates in place, there is no need to treat the DASD as unsupported devices. It apparently IS possible to dedicate a device to more than one guest (tricksy, it is). While doing some IOCP research, I came across this in the description of the CNTLUNIT statement for IOCP: When you are running VM with guest operating systems, you can use multiple CNTLUNIT statements for a single physical control unit in certain environments to effectively dedicate the same physical devices to more than one guest. This technique involves potential path-grouping considerations that create operational complications. Ensure you have determined possible consequences and that you use caution if employing this technique. Caveat emptor. Alan Altmark z/VM and Linux on System z Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 alan_altm...@us.ibm.com IBM Endicott
Re: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory
On Friday, 11/05/2010 at 11:30 EDT, Mike Walter mike.wal...@hewitt.com wrote: But now the wrinkle. Some very clever high-speed z/OS ISV software is issuing some unsupported (by z/VM) CCWs to that DASD. For those CCWs to work, I'll need to define the DASD in SYSTEM CONFIG using the RDEVICE statement to tell CP to keep its mitts off the CCWs as: RDEVICE rdev-rdev TYPE UNSUPPORTED DEVCLASS DASD ... Unfortunately, the doc for the RDEVICE statement relates: Note: When you define an unsupported device, you must dedicate the device to a virtual machine. To do this, specify the DEDICATE directory control statement in the virtual machine?s directory statement or issue the CP ATTACH command One cannot DEDICATE or ATTACH devices to one guest when they need to be shared by all three guests. Have I missed/forgotten some obscure technique to manage this? Nope, you have the right of it. Contact the Support Center for assistance. Depending on the particulars, there may be a fix or circumvention available. Alan Altmark z/VM and Linux on System z Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 alan_altm...@us.ibm.com IBM Endicott
Re: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory
Both HDS and EMC have provided CP updates to the CCW translation tables. In fact, for 6.1 IBM has included the updates that HDS has supported for the last several releases. With those updates in place, there is no need to treat the DASD as unsupported devices. Regards, Richard Schuh -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mike Walter Sent: Friday, November 05, 2010 8:30 AM To: IBMVM@LISTSERV.UARK.EDU Subject: RDEVICE DASD rdev TYPE UNSUPPORTED DEVCLASS DASD vs DEVNO in directory We have some non-IBM DASD which is shared R/W by three z/OS guests. To permit the z/OS folks to relabel their DASD any time they wish, the directory entries use the MDISK DEVNO operand, looking a bit (changed for ease of understanding) like... USER NO_LOGON ... ... MDISK A300 3390 DEVNO A300 RV readpw writepw multpw ... USER ZOSSYS1 ... ... LINK NO_LOGON A300 A00 MW ... USER ZOSSYS2 ... ... LINK NO_LOGON A300 A00 MW ... USER ZOSSYS3 ... ... LINK NO_LOGON A300 A00 MW ... That has been working great for many years. But now the wrinkle. Some very clever high-speed z/OS ISV software is issuing some unsupported (by z/VM) CCWs to that DASD. For those CCWs to work, I'll need to define the DASD in SYSTEM CONFIG using the RDEVICE statement to tell CP to keep its mitts off the CCWs as: RDEVICE rdev-rdev TYPE UNSUPPORTED DEVCLASS DASD ... Unfortunately, the doc for the RDEVICE statement relates: Note: When you define an unsupported device, you must dedicate the device to a virtual machine. To do this, specify the DEDICATE directory control statement in the virtual machine?s directory statement or issue the CP ATTACH command One cannot DEDICATE or ATTACH devices to one guest when they need to be shared by all three guests. Have I missed/forgotten some obscure technique to manage this? Mike Walter Aon Corporation The opinions expressed herein are mine alone, not my employer's. 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.
