Adding different sized page volumes
Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group _ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/201469229/direct/01/
Re: Adding different sized page volumes
Hello Mark, I have been always told that PAGE and SPOOL volumes should be kept separate from all other drives. Ed Martin Aultman Health Foundation 330-363-5050 ext 35050 From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 10:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now. http://clk.atdmt.com/GBL/go/201469229/direct/01/
Re: Adding different sized page volumes
Correct. If I only allocated cyls 1-10016, the rest of the 3390-27 would remain free. Date: Tue, 23 Feb 2010 10:03:54 -0500 From: emar...@aultman.com Subject: Re: Adding different sized page volumes To: IBMVM@LISTSERV.UARK.EDU Hello Mark, I have been always told that PAGE and SPOOL volumes should be kept separate from all other drives. Ed Martin Aultman Health Foundation 330-363-5050 ext 35050 From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 10:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now. _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469227/direct/01/
Re: Adding different sized page volumes
Regards, Richard Schuh From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 7:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now.http://clk.atdmt.com/GBL/go/201469229/direct/01/
Re: Adding different sized page volumes
My experience was that the paging will be spread evenly until the -9s start filling up and then the additional space in the -27s will be used. That was from a recent experience with a combination of -3s and -9s. I have since converted everything to -9s. The only possible answer to the other question is, It depends. If your system is not paging to DASD very much, it probably doesn't matter. If you are paging to DASD, then the lower the space utilization, the more likely that the system can realize the benefits of block paging. Regards, Richard Schuh From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 7:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now.http://clk.atdmt.com/GBL/go/201469229/direct/01/
Re: Adding different sized page volumes
Yes, we're paging. A lot! And the page volumes are filling up too! Some new 3390-27 page volumes have been added, with all 32K cyls allocated to PAGE, and when the 3390-9's fill up, the mod27's do go beyond the 10016 cyl mark. I suspect (we haven't gotten this far yet) that when the mod 9's completely fill up, not only will block paging suffer (more), but most of the page-outs will be concentrated on the relatively few mod 27s. Gaackkk! I'm just trying to reconcile the admonishment not to mix page volume sizes with what people do in the real world. Since my options don't provide for the *ideal* solution, my preference is to adopt one that will provide the maximum benefit with the smallest downside. Best regards, Mark Date: Tue, 23 Feb 2010 08:37:06 -0800 From: rsc...@visa.com Subject: Re: Adding different sized page volumes To: IBMVM@LISTSERV.UARK.EDU My experience was that the paging will be spread evenly until the -9s start filling up and then the additional space in the -27s will be used. That was from a recent experience with a combination of -3s and -9s. I have since converted everything to -9s. The only possible answer to the other question is, It depends. If your system is not paging to DASD very much, it probably doesn't matter. If you are paging to DASD, then the lower the space utilization, the more likely that the system can realize the benefits of block paging. Regards, Richard Schuh From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 7:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now. _ Hotmail: Free, trusted and rich email service. http://clk.atdmt.com/GBL/go/201469228/direct/01/
Re: Adding different sized page volumes
Mark, Yes, we're paging. A lot! And the page volumes are filling up too! Not being a performance geek, and without any knowledge of your environment other except that you have Linux for System z guests, something sounds a little fishy. Just guessing from other's past posts: could it be that your Linux guests had been given VM sizes based on what the distributed servers had? IIRC, Linux caches a lot of files in its storage. That's great in a distributed server that has lower I/O throughput (all I/O is serviced by the CPU on the motherboard vs. being handed off to an I/O processor on System z), and where distributed memory is a lot cheaper than System z memory. On System z, memory is (relatively) expensive, I/O's are VERY fast (and do not impact the CPU much), and MDISK cache is quite good. Giving Linux for System z servers lots of memory because that's what they had on distributed servers (presuming that the memory is mostly file caching), and having the Linux server also cached in minidisk cache is quite a waste (double caching). IIRC, MDCACHE beats Linux cache in almost every case. If you have a good performance monitor for your Linux guests, try to see *why* they need so much memory. If it's file cache, try reducing the vm size significantly (IIRC, Jim Vincent used to recommend 2G or less for Websphere servers). Getting the Linux guest memory requirements reduced could improve your z/VM paging requirements. Good hunting! Mike Walter Hewitt Associates The opinions expressed herein are mine alone, not my employer's. Mark Wheeler mwheele...@hotmail.com Sent by: The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU 02/23/2010 11:01 AM Please respond to The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU To IBMVM@LISTSERV.UARK.EDU cc Subject Re: Adding different sized page volumes Yes, we're paging. A lot! And the page volumes are filling up too! Some new 3390-27 page volumes have been added, with all 32K cyls allocated to PAGE, and when the 3390-9's fill up, the mod27's do go beyond the 10016 cyl mark. I suspect (we haven't gotten this far yet) that when the mod 9's completely fill up, not only will block paging suffer (more), but most of the page-outs will be concentrated on the relatively few mod 27s. Gaackkk! I'm just trying to reconcile the admonishment not to mix page volume sizes with what people do in the real world. Since my options don't provide for the *ideal* solution, my preference is to adopt one that will provide the maximum benefit with the smallest downside. Best regards, Mark Date: Tue, 23 Feb 2010 08:37:06 -0800 From: rsc...@visa.com Subject: Re: Adding different sized page volumes To: IBMVM@LISTSERV.UARK.EDU My experience was that the paging will be spread evenly until the -9s start filling up and then the additional space in the -27s will be used. That was from a recent experience with a combination of -3s and -9s. I have since converted everything to -9s. The only possible answer to the other question is, It depends. If your system is not paging to DASD very much, it probably doesn't matter. If you are paging to DASD, then the lower the space utilization, the more likely that the system can realize the benefits of block paging. Regards, Richard Schuh From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 7:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now. Hotmail: Free, trusted and rich email service. Get it now. 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
Re: Adding different sized page volumes
are you able to move stuff off existing mod 9 over to the 27s and free some up? 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 Mark Wheeler Sent: Tuesday, February 23, 2010 9:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: [IBMVM] Adding different sized page volumes Yes, we're paging. A lot! And the page volumes are filling up too! Some new 3390-27 page volumes have been added, with all 32K cyls allocated to PAGE, and when the 3390-9's fill up, the mod27's do go beyond the 10016 cyl mark. I suspect (we haven't gotten this far yet) that when the mod 9's completely fill up, not only will block paging suffer (more), but most of the page-outs will be concentrated on the relatively few mod 27s. Gaackkk! I'm just trying to reconcile the admonishment not to mix page volume sizes with what people do in the real world. Since my options don't provide for the *ideal* solution, my preference is to adopt one that will provide the maximum benefit with the smallest downside. Best regards, Mark Date: Tue, 23 Feb 2010 08:37:06 -0800 From: rsc...@visa.com Subject: Re: Adding different sized page volumes To: IBMVM@LISTSERV.UARK.EDU My experience was that the paging will be spread evenly until the -9s start filling up and then the additional space in the -27s will be used. That was from a recent experience with a combination of -3s and -9s. I have since converted everything to -9s. The only possible answer to the other question is, It depends. If your system is not paging to DASD very much, it probably doesn't matter. If you are paging to DASD, then the lower the space utilization, the more likely that the system can realize the benefits of block paging. Regards, Richard Schuh From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Mark Wheeler Sent: Tuesday, February 23, 2010 7:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Adding different sized page volumes Greetings all, We need to add more page volumes (for both space and actuators) but are fresh out of 3390-9's. If we throw 3390-27's into the mix, should they be fully allocated as PAGE, or just cyls 1-10016? Will I start a religous war if I also ask about the latest recommendation for page volume space utilization? Max of 25%? 50%? It Depends? Best regards, Mark Wheeler UnitedHealth Group Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now. http://clk.atdmt.com/GBL/go/201469229/direct/01/ Hotmail: Free, trusted and rich email service. Get it now. http://clk.atdmt.com/GBL/go/201469228/direct/01/
Re: Adding different sized page volumes
We will, to the extent we can, but not quickly enough to avoid using mod27's as a stop-gap for now. Date: Tue, 23 Feb 2010 11:28:18 -0600 From: marcy.d.cor...@wellsfargo.com Subject: Re: Adding different sized page volumes To: IBMVM@LISTSERV.UARK.EDU are you able to move stuff off existing mod 9 over to the 27s and free some up? Marcy _ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469226/direct/01/
Re: Adding different sized page volumes
That's why we converted everything to -9s as quickly as we could. The mixed size configuration was in reaction to a crisis. All were made -9s before the next IPL. It took time to (a) obtain the new DASD (it was in-house as MVS spares, connected to VM , but offline), (b) format it and (c) update the SYSTEM CONFIG file. Regards, Richard Schuh Some new 3390-27 page volumes have been added, with all 32K cyls allocated to PAGE, and when the 3390-9's fill up, the mod27's do go beyond the 10016 cyl mark. I suspect (we haven't gotten this far yet) that when the mod 9's completely fill up, not only will block paging suffer (more), but most of the page-outs will be concentrated on the relatively few mod 27s. Gaackkk!
Re: Adding different sized page volumes
Mike, We have done a lot of optimizing of virtual machine sizes, and have a bit more work to do there. The problem is that demand for new servers has outpaced the resources (CPU, memory, page space) available to us. New processor and memory capacity is coming soon, but we're trying everything possible that will help us survive until that happy day! This is a good problem to have, actually... ;-) The paging subsystem config needs to be beefed up, even with the new memory capacity. Best regards, Mark Date: Tue, 23 Feb 2010 11:23:45 -0600 From: mike.wal...@hewitt.com Subject: Re: Adding different sized page volumes To: IBMVM@LISTSERV.UARK.EDU Mark, Yes, we're paging. A lot! And the page volumes are filling up too! Not being a performance geek, and without any knowledge of your environment other except that you have Linux for System z guests, something sounds a little fishy. _ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/201469229/direct/01/
Re: Adding different sized page volumes
Look at past SHARE presentations on the subject as well the Redbooks. They carry a wealth of information related to Linux guests and paging. Jim On 2/23/2010 12:23 PM, Mike Walter wrote: Mark, Yes, we're paging. A lot! And the page volumes are filling up too! Not being a performance geek, and without any knowledge of your environment other except that you have Linux for System z guests, something sounds a little fishy. Just guessing from other's past posts: could it be that your Linux guests had been given VM sizes based on what the distributed servers had? IIRC, Linux caches a lot of files in its storage. That's great in a distributed server that has lower I/O throughput (all I/O is serviced by the CPU on the motherboard vs. being handed off to an I/O processor on System z), and where distributed memory is a lot cheaper than System z memory. On System z, memory is (relatively) expensive, I/O's are VERY fast (and do not impact the CPU much), and MDISK cache is quite good. Giving Linux for System z servers lots of memory because that's what they had on distributed servers (presuming that the memory is mostly file caching), and having the Linux server also cached in minidisk cache is quite a waste (double caching). IIRC, MDCACHE beats Linux cache in almost every case. If you have a good performance monitor for your Linux guests, try to see *why* they need so much memory. If it's file cache, try reducing the vm size significantly (IIRC, Jim Vincent used to recommend 2G or less for Websphere servers). Getting the Linux guest memory requirements reduced could improve your z/VM paging requirements. Good hunting! Mike Walter Hewitt Associates The opinions expressed herein are mine alone, not my employer's.
Re: Adding different sized page volumes
CP keeps an eye on the performance of the page volumes when it has to select a device to page out. The fastest device will win. If that happens to be a small 3390 with an occupancy of e.g. 50%, it may be a bad choice as the block paging will be less effective. So: if you have enough volumes to keep them all relatively empty, you can mix volumes of different capacities. 2010/2/23 Jim Bohnsack jab...@cornell.edu Look at past SHARE presentations on the subject as well the Redbooks. They carry a wealth of information related to Linux guests and paging. Jim On 2/23/2010 12:23 PM, Mike Walter wrote: Mark, Yes, we're paging. A lot! And the page volumes are filling up too! Not being a performance geek, and without any knowledge of your environment other except that you have Linux for System z guests, something sounds a little fishy. Just guessing from other's past posts: could it be that your Linux guests had been given VM sizes based on what the distributed servers had? IIRC, Linux caches a lot of files in its storage. That's great in a distributed server that has lower I/O throughput (all I/O is serviced by the CPU on the motherboard vs. being handed off to an I/O processor on System z), and where distributed memory is a lot cheaper than System z memory. On System z, memory is (relatively) expensive, I/O's are VERY fast (and do not impact the CPU much), and MDISK cache is quite good. Giving Linux for System z servers lots of memory because that's what they had on distributed servers (presuming that the memory is mostly file caching), and having the Linux server also cached in minidisk cache is quite a waste (double caching). IIRC, MDCACHE beats Linux cache in almost every case. If you have a good performance monitor for your Linux guests, try to see *why* they need so much memory. If it's file cache, try reducing the vm size significantly (IIRC, Jim Vincent used to recommend 2G or less for Websphere servers). Getting the Linux guest memory requirements reduced could improve your z/VM paging requirements. Good hunting! Mike Walter Hewitt Associates The opinions expressed herein are mine alone, not my employer's. -- Kris Buelens, IBM Belgium, VM customer support
