Re: How much memory?
Guys, Thanks for all your help. Unfortunately management (at MD level) have shot this idea down. Sometimes, I wonder if there is any commitment at all for the mainframe platform
Re: How much memory?
He can share the storage if the Linux guest is a virtual machine, but he won't be able to use the IFL AND his general purpose CP(s) in the same LPAR. He'd need a z10 with an LPAR configured with the new ZVM support to mix/match different processors in the same LPAR. This was actually our justification for getting a z10, the ability to mix IFL's and CP's in the same LPAR. :) PS: How much storage you need for your Linux LPAR depends on what you want to use Linux for, but I've run production Linux systems (SuSE, RedHat and Debian) in just a few hundred MB and they ran Apache web servers, LVM, DB2/Connect, mail servers and a ton of other stuff with no problems. :) -Mike -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Scott Rohling Sent: Monday, September 14, 2009 10:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: How much memory? It will depend on what your POC encompasses.. how many Linux guests? What software/middleware?. You might want to consider a 2nd level guest rather than building a separate LPAR -- that way you can manage things under a single zVM and dynamically change things (give your 2nd level zVM more storage, for example) much more easily... Scott On Mon, Sep 14, 2009 at 7:52 AM, Vince Getgood vincent.getg...@xchanging.com wrote: Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR without hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. Comments and opinions welcome.
How much memory?
Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR withou t hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. Comments and opinions welcome.
Re: How much memory?
It will depend on what your POC encompasses.. how many Linux guests? What software/middleware?. You might want to consider a 2nd level guest rather than building a separate LPAR -- that way you can manage things under a single zVM and dynamically change things (give your 2nd level zVM more storage, for example) much more easily... Scott On Mon, Sep 14, 2009 at 7:52 AM, Vince Getgood vincent.getg...@xchanging.com wrote: Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR without hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. Comments and opinions welcome.
Re: How much memory?
On Mon, Sep 14, 2009 at 3:52 PM, Vince Getgood vincent.getg...@xchanging.com wrote: Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR without hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. The real answer will be in z/VM monitor data. But as long as z/VM has enough memory it is not easy to tell what would happen when it had less. You probably can do with 1G. You should not expect z/VM to overcommit memory for the two z/OS guests, so you need the memory available for that. The remaining service machines will probably do fine in 256 MB real memory. And you should make sure you do have some paging space to make up for the difference... Your Linux workload can probably use all the memory you can give it. And I do hope you don't have too high expectations of the z800 IFL (they're a bit slow for today's standards with Linux). Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/
Re: How much memory?
On a 2G z/VM system, we run one OS/390 machine (128M), two z/OS machines (512M 1024M), three z/VSE machines (128M each) and four Linux machines (3 at 2048M and one at 256M/512M). But our configuration is not a production environment. On Mon, Sep 14, 2009 at 7:02 AM, Gentry, Stephen stephen.gen...@lafayettelife.com wrote: 2gb would be a good starting point. When we did a POC, we had a little over 7gb available and we could run 3 Linux guests, running DB2, comfortably. -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Vince Getgood Sent: Monday, September 14, 2009 9:53 AM To: IBMVM@LISTSERV.UARK.EDU Subject: How much memory? Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR withou t hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. Comments and opinions welcome. -- Daniel Allen | Serena Software, Inc. | Senior Systems Programmer - Mainframe Services Phone: 1-800-457-3736x11241
Re: How much memory?
2gb would be a good starting point. When we did a POC, we had a little over 7gb available and we could run 3 Linux guests, running DB2, comfortably. -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Vince Getgood Sent: Monday, September 14, 2009 9:53 AM To: IBMVM@LISTSERV.UARK.EDU Subject: How much memory? Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR withou t hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. Comments and opinions welcome.
Re: How much memory?
My initial guess is that you need about 1 GB for your current workload. Some things to check: 1. Do a QSYSOWN qsysown ** Summary Information: Total-Pages TypeAllocd In-Use %-Used SPOL 1201680 348517 29.0 PAGE 1201680 172559 14.4 Look at the %-Used for PAGE. If it is near zero, where it should be if you never paged, great. If it is not near zero, then you did/have been paging. 2. Find how much storage you are using. Do an IND USER for each guest: ind user stlesa2 USERID=STLESA2 MACH=ESA STOR=700M VIRT=V XSTORE=NONE IPLSYS=DEV 0120 DEVNUM=00073 PAGES: RES=00021448 WS=00021444 LOCKEDREAL=0004 RESVD= NPREF=00011685 PREF= READS=00015515 WRITES=00051555 XSTORE=000646 READS=003233 WRITES=025769 MIGRATES=021694 CPU 00: CTIME=92:37 VTIME=721:27 TTIME=839:31 IO=335062 RDR=015839 PRT=790969 PCH=078332 Look at the RES figure. This is the number of pages that machine is using now. Sum up all the pages for all the currently logged on machines, multiply by 4K an that is the storage your guests are using. 3. Do a Q FRAMES: q frames All Frames: Configured=163839 Real=163839 Usable=163839 Offline=0 Pageable=148743 NotInitialized=0 GlobalClearedAvail=32 LocalClearedAvail=32 LocalUnclearedAvail=31 The Configured minus Pageablejust say VM overhead. Sum up 2 and 3 and that is the amount of storage you need at your current paging rate (which should be near zero). My guess is you have 6 GB left. 1 GB for your system. 1 GB taken for microcode. 6 GB remaining. Taking 2 GB for the zLinux LPAR is a good start. You will have a little more than a GB for Linux stuff. On the Linux LPAR, make sure you have 4+ full paging packs, as you are going to page here. Perhaps give .5 GB for expanded storage, also, as you are going to page here. Don't forget to implement vdisk support so you have vdisk packs for Linux swap areas. Good time to also bring up vswitch/guest LAN. Of course if you have a performance monitor, getting the right amount of storage is a lot easier, but it is also doable manually. How often can you reconfigure your production LPAR? If rare, push for a performance monitor as it will save you Power On Resets as you keep reconfiguring your production LPAR. If you can do it weekly/monthly, well, take 2 GB, monitor for a while, take another 1 GB, monitor for a while, take another GB, perhaps give back 512 MB. You know the drill. Tom Duerbusch THD Consulting Vince Getgood vincent.getg...@xchanging.com 9/14/2009 8:52 AM Hi all, I'm not a VM expert, so forgive me if this seems a newbie quetion. I have a z800 running z/VM, which has two production z/OS guests, and the usual collection of CMS guests (TCPIP / OPERATOR etc). We discovered recently that the z800 has an IFL (long story - don't ask!) and would like to steal some of the 8GB currently allocated to VM, to run up a VM / Linux LPAR for a POC. The two z/OS guests are defined at 256MB 512MB (Bill Gates, are you watching??), and don't page. In your most esteemed opinion, what could I steal from the VM LPAR without hurting it's and the guests performance / making it page? Personally, I think 2GB would be enough. Comments and opinions welcome.
