Re: Number of IFLs to zLinux guests
All very good points. We do have a good monitor we just need to learn how to use it and what to look for. It will just take time. Thanks to all for the input it has been very helpful! Thanks, Nick -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Mark Post Sent: Thursday, March 20, 2008 12:29 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Number of IFLs to zLinux guests On Wed, Mar 19, 2008 at 3:20 PM, in message [EMAIL PROTECTED], Harris, Nick J. [EMAIL PROTECTED] wrote: Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? No. I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. The question that comes to my mind is why would you care? My reaction is that you're trying to manage performance and capacity by gut feel and rules of thumb. If so, that's a good way to ensure failure at some point. You need the proper tools to monitor both and make rational, fact-based decisions. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. If you are experiencing bad performance, you may nor may not need to add capacity, which is where having a good monitor can help you be sure. If you're having good performance, for all you know you could put several hundred guests on those two IFLs. Or, maybe the next test system will crater you. If you don't have good measurements, all the rules of thumb in the world won't help you. Mark Post
Re: Number of IFLs to zLinux guests
I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. The question that comes to my mind is why would you care? My reaction is that you're trying to manage performance and capacity by gut feel and rules of thumb. Or... perhaps he's trying to get an idea of how much hardware (and the associated costs) is required to support a planned Linux on System z project? If that's the case, then he should contact his local IBM reps or IBM Business Partner and work with them to perform a TCO analysis of the current workload being considered for consolidation onto System z hardware. IBM has some very comprehensive TCO analysis tools, and appears to very much enjoy running them. Mike Walter Hewitt Associates Any opinions expressed herein are mine alone and do not necessarily represent the opinions or policies of Hewitt Associates. Mark Post [EMAIL PROTECTED] Sent by: The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU 03/20/2008 12:28 AM Please respond to The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU To IBMVM@LISTSERV.UARK.EDU cc Subject Re: Number of IFLs to zLinux guests On Wed, Mar 19, 2008 at 3:20 PM, in message [EMAIL PROTECTED], Harris, Nick J. [EMAIL PROTECTED] wrote: Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? No. I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. The question that comes to my mind is why would you care? My reaction is that you're trying to manage performance and capacity by gut feel and rules of thumb. If so, that's a good way to ensure failure at some point. You need the proper tools to monitor both and make rational, fact-based decisions. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. If you are experiencing bad performance, you may nor may not need to add capacity, which is where having a good monitor can help you be sure. If you're having good performance, for all you know you could put several hundred guests on those two IFLs. Or, maybe the next test system will crater you. If you don't have good measurements, all the rules of thumb in the world won't help you. Mark Post 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: Number of IFLs to zLinux guests
On Thu, Mar 20, 2008 at 3:09 PM, Harris, Nick J. [EMAIL PROTECTED] wrote: All very good points. We do have a good monitor we just need to learn how to use it and what to look for. It will just take time. I think it is good to look at your configuration and estimate how many more you could run without hurting yourself. Or to look at your deployment plans and come up with an estimate of how many IFLs you would need to get. Your own Linux servers are the best ones to compare... Look at your overall utilization breakdown and see how many % of a CPU each Linux uses. With Linux on z/VM, the low-hanging fruit is the servers that are under-utilized. When they are used only 5% of the time, you could in theory have 20 of them on a single CPU. Obviously when two servers want their share at the same moment, they would be competing and get delayed. Not as bad as you would fear because many applications have periods where they don't use much CPU, even when they are busy (because they do disk I/O or wait for network data). And this works out better with many CPUs and many Linux servers. But even with a few dozen, you want to look at their idle usage. When the Linux server has all kind of other good stuff in addition to running your application (like checking for software updates, keep active agents running, etc) then that idle load does start to count. With 20 servers using 2.5% of a CPU when idle, you already use half a CPU. That means the business workload must do with just the other half. The lower you get their CPU usage in idle periods, the better. It is not uncommon to have the idle server use less than 0.5% of a CPU when you have stopped various useless background noise. Often the next issue is memory usage. When your your Linux server is idle for a longer period, z/VM should be able to take away some of the memory resources and give it to the servers that are busy at that time. Much of that comes from proper sizing, and also making sure they get really idle (so z/VM will notice that and take resources away). If you're into this, performance classes and conferences are probably worth the investment. Rob -- Rob van der Heij Velocity Software GmbH http://velocitysoftware.com/
Re: Number of IFLs to zLinux guests
You can use SET SHARE to stop the CPU runaways. We have one bad app server we decided to cap permanently. The application code problems have actully been on a Windows server -but it impacts the oracle db on the mainframe- we just capped the test db server so it doesn't impact the other servers. -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of RPN01 Sent: Wednesday, March 19, 2008 3:56 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Number of IFLs to zLinux guests We're running about 40 Linux guests on a total of four IFLs, spread across two LPARs and CECs. Roughly 20 guests in each LPAR. We're about to add an additional IFL to each LPAR, not for capacity, since we're normally running at about 10 - 20 percent, but to handle the case where a single rogue guest consumes everything it can get for awhile. We'll continue to build one and two virtual CPU guests, but have the third engine to avoid allowing a single guest with dual virtual CPUs from eating the entire system. -- Robert P. Nix Mayo Foundation.~. RO-OE-5-55 200 First Street SW/V\ 507-284-0844 Rochester, MN 55905 /( )\ -^^-^^ In theory, theory and practice are the same, but in practice, theory and practice are different. On 3/19/08 2:36 PM, Marcy Cortes [EMAIL PROTECTED] wrote: z9 ECs here and a z10, but I'm not counting him yet... In prod - we have 45 or so guests on 18 IFLs In test - we have had 100 or so guests on 2 IFLs. So, the ratio is either 50:1 or 5:2 :) You can see why everyone says it depends. If you can get the testers to play well together (wiki page coordination is what we do), I think one could have a ratio to work with in test. Prod is going to require measurement and planning :) Memory is usually a bigger issue than CPU. At least with CPU you can prioritize things so not all feel it. If you are heavily paging, everyone feels it. (i.e 100 on 24G = pain, 100 on 48G = happiness) (PS. We started with 2 :) Marcy Cortes 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:[EMAIL PROTECTED] On Behalf Of Harris, Nick J. Sent: Wednesday, March 19, 2008 12:20 PM To: IBMVM@LISTSERV.UARK.EDU Subject: [IBMVM] Number of IFLs to zLinux guests Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. TIA Thanks, Nick Harris Lead Systems Programmer Texas Farm Bureau Mutual Insurance Company 7420 Fish Pond Rd. Waco, TX 76710 254.751.2259 [EMAIL PROTECTED] * This communication, including attachments, is for the exclusive use of addressee and may contain proprietary, confidential and/or privileged information. If you are not the intended recipient, any use, copying, disclosure, dissemination or distribution is strictly prohibited. If you are not the intended recipient, please notify the sender immediately by return e-mail, delete this communication and destroy all copies. *
Re: Number of IFLs to zLinux guests
It depends. The cpu power of a z9 (or now z10) is larger than a z9BC.You need to consider what 'size' IFL's you're talking about, what kind of applications- do they do a lot of I/O use cpu, use memory, etc. From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Harris, Nick J. Sent: Wednesday, March 19, 2008 3:20 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Number of IFLs to zLinux guests Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. TIA Thanks, Nick Harris Lead Systems Programmer Texas Farm Bureau Mutual Insurance Company 7420 Fish Pond Rd. Waco, TX 76710 254.751.2259 [EMAIL PROTECTED] * This communication, including attachments, is for the exclusive use of addressee and may contain proprietary, confidential and/or privileged information. If you are not the intended recipient, any use, copying, disclosure, dissemination or distribution is strictly prohibited. If you are not the intended recipient, please notify the sender immediately by return e-mail, delete this communication and destroy all copies. *
Re: Number of IFLs to zLinux guests
In which case my question would have been the same. Asking other people what kind of mileage they get out of their systems is likely to be totally irrelevant. It depends doesn't even begin to cover it. As another responder suggested, he'd be far better off looking at his current workload and extrapolating from that. Mike Walter [EMAIL PROTECTED] 03/20/08 10:29 AM I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. The question that comes to my mind is why would you care? My reaction is that you're trying to manage performance and capacity by gut feel and rules of thumb. Or... perhaps he's trying to get an idea of how much hardware (and the associated costs) is required to support a planned Linux on System z project?
Re: Number of IFLs to zLinux guests
z9 ECs here and a z10, but I'm not counting him yet... In prod - we have 45 or so guests on 18 IFLs In test - we have had 100 or so guests on 2 IFLs. So, the ratio is either 50:1 or 5:2 :) You can see why everyone says it depends. If you can get the testers to play well together (wiki page coordination is what we do), I think one could have a ratio to work with in test. Prod is going to require measurement and planning :) Memory is usually a bigger issue than CPU. At least with CPU you can prioritize things so not all feel it. If you are heavily paging, everyone feels it. (i.e 100 on 24G = pain, 100 on 48G = happiness) (PS. We started with 2 :) Marcy Cortes 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:[EMAIL PROTECTED] On Behalf Of Harris, Nick J. Sent: Wednesday, March 19, 2008 12:20 PM To: IBMVM@LISTSERV.UARK.EDU Subject: [IBMVM] Number of IFLs to zLinux guests Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. TIA Thanks, Nick Harris Lead Systems Programmer Texas Farm Bureau Mutual Insurance Company 7420 Fish Pond Rd. Waco, TX 76710 254.751.2259 [EMAIL PROTECTED]
Re: Number of IFLs to zLinux guests
We're running about 40 Linux guests on a total of four IFLs, spread across two LPARs and CECs. Roughly 20 guests in each LPAR. We're about to add an additional IFL to each LPAR, not for capacity, since we're normally running at about 10 - 20 percent, but to handle the case where a single rogue guest consumes everything it can get for awhile. We'll continue to build one and two virtual CPU guests, but have the third engine to avoid allowing a single guest with dual virtual CPUs from eating the entire system. -- Robert P. Nix Mayo Foundation.~. RO-OE-5-55 200 First Street SW/V\ 507-284-0844 Rochester, MN 55905 /( )\ -^^-^^ In theory, theory and practice are the same, but in practice, theory and practice are different. On 3/19/08 2:36 PM, Marcy Cortes [EMAIL PROTECTED] wrote: z9 ECs here and a z10, but I'm not counting him yet... In prod - we have 45 or so guests on 18 IFLs In test - we have had 100 or so guests on 2 IFLs. So, the ratio is either 50:1 or 5:2 :) You can see why everyone says it depends. If you can get the testers to play well together (wiki page coordination is what we do), I think one could have a ratio to work with in test. Prod is going to require measurement and planning :) Memory is usually a bigger issue than CPU. At least with CPU you can prioritize things so not all feel it. If you are heavily paging, everyone feels it. (i.e 100 on 24G = pain, 100 on 48G = happiness) (PS. We started with 2 :) Marcy Cortes 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:[EMAIL PROTECTED] On Behalf Of Harris, Nick J. Sent: Wednesday, March 19, 2008 12:20 PM To: IBMVM@LISTSERV.UARK.EDU Subject: [IBMVM] Number of IFLs to zLinux guests Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. TIA Thanks, Nick Harris Lead Systems Programmer Texas Farm Bureau Mutual Insurance Company 7420 Fish Pond Rd. Waco, TX 76710 254.751.2259 [EMAIL PROTECTED]
Re: Number of IFLs to zLinux guests
You could play it politically safe and start with the same sort of ratio that your organization's Windows Virtualization people are using (http://communities.vmware.com/thread/128660?tstart=30). Then when you see that your processors are not fully utilized and you still have paging capacity, you can add more guests while the Windows group needs to ask fo r more hardware. /Tom Kern On Wed, 19 Mar 2008 14:20:19 -0500, Harris, Nick J. [EMAIL PROTECTED] wrote: Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC.
Re: Number of IFLs to zLinux guests
You can definitely run short of CPU if your guests are CPU intensive. we have 40-50 guests on 2 z990 IFLs see http://www.linuxvm.org/Present/SHARE110/S9284ps.pdf see page 11-13 This e-mail, including any attachments, may be confidential, privileged or otherwise legally protected. It is intended only for the addressee. If you received this e-mail in error or from someone who was not authorized to send it to you, do not disseminate, copy or otherwise use this e-mail or its attachments. Please notify the sender immediately by reply e-mail and delete the e-mail from your system. From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Harris, Nick J. Sent: Wednesday, March 19, 2008 3:20 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Number of IFLs to zLinux guests Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. TIA Thanks, Nick Harris Lead Systems Programmer Texas Farm Bureau Mutual Insurance Company 7420 Fish Pond Rd. Waco, TX 76710 254.751.2259 [EMAIL PROTECTED]
Re: Number of IFLs to zLinux guests
We have about a dozen running on a single z9BC IFL. -- Mark Pace Mainline Information Systems
Re: Number of IFLs to zLinux guests
On Wed, 19 Mar 2008 14:20:19 -0500, Harris, Nick J. [EMAIL PROTECTED] wrote: Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We run 8 production and 7 test guests on a z9bc with 2 IFLs. The CPU capacity could support another handful or two, depending on what got adde d. Brian Nielsen
Re: Number of IFLs to zLinux guests
On Wed, Mar 19, 2008 at 3:20 PM, in message [EMAIL PROTECTED], Harris, Nick J. [EMAIL PROTECTED] wrote: Hello All, Is there a golden rule about the number of IFLs to support production Linux guests? No. I understand all shops are different and 'it depends' applies...but we are curious as to the ratio of IFLs to Linux guest in other shops. The question that comes to my mind is why would you care? My reaction is that you're trying to manage performance and capacity by gut feel and rules of thumb. If so, that's a good way to ensure failure at some point. You need the proper tools to monitor both and make rational, fact-based decisions. Are there any shops out there running zLinux guests in production under z/VM with two or less IFLs besides us? We have four production Linux guests and twenty one test Linux guests supported by two IFLs on a z9BC. If you are experiencing bad performance, you may nor may not need to add capacity, which is where having a good monitor can help you be sure. If you're having good performance, for all you know you could put several hundred guests on those two IFLs. Or, maybe the next test system will crater you. If you don't have good measurements, all the rules of thumb in the world won't help you. Mark Post
