I haven't added it all up, but we do it that way and would have to be either right around 275G if not over.
One thing to look out for is the vm.swappiness setting. Seems that on SLES 9 (latest kernel) some virtual machines have a tendency to just keep writing more and more to swap and never free up those pages in vdisk until the process is stopped. We had production machines march through all their space and then java core dump :(. Used page space was also growing too quickly without it. Yes, swapoff/swapon would free up those pages (but the structures would still exist in VM). Setting kernel parameter vm.swappiness=20 seemed to prevent that. Don't ask me why... It just does :) (no time to go read the code and truly understand that)... The default is 60. PS. We use mod 3's for paging and mod 27's mostly for everything else. 9's seem kind of useless after you build a file system on them and only have like 6-something Gig left. 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." -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Rob van der Heij Sent: Monday, December 03, 2007 11:04 AM To: [email protected] Subject: Re: [LINUX-390] Is 275GB of VDISK stupid? On Dec 3, 2007 7:54 PM, Bill Bitner <[EMAIL PROTECTED]> wrote: > This is a good approach, but please one reminder. The DAT structures > for virtual disk in storage address spaces, including PGMBKs, are not > pageable (user space PGMBKs are). And prior to z/VM 5.3.0, they must > reside in real memory below 2GB. So 275GB of vdisk would be more than > 2GB of memory required below 2GB for the DAT structures. One would > want to be on z/VM 5.3.0. The PGMBKs are not reflected in the PTRM > numbers. But only when used, isn't it? As long as you have not touched them, there's no PGMBKs except for the first one. Once he actually starts using them I would think that 550 GB of paging space might approach some other limitations in CP (though with 3390-9 not the number of cpowned volumes). -Rob -- Rob van der Heij Velocity Software, Inc http://velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
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