z/OS does not use Xstore anymore. Jerry Whitteridge Mainframe Engineering
Safeway Inc 925 951 4184 [email protected] If everything seems under control, you're just not going fast enough. ________________________________ From: The IBM z/VM Operating System [mailto:[email protected]] On Behalf Of Schuh, Richard Sent: Wednesday, March 04, 2009 2:41 PM To: [email protected] Subject: Re: XSTORE I don't think that z/OS uses XSTORE. Our MVS sysprogs expressed surprise that we had some defined for VM. Regards, Richard Schuh ________________________________ From: The IBM z/VM Operating System [mailto:[email protected]] On Behalf Of David Boyes Sent: Wednesday, March 04, 2009 11:02 AM To: [email protected] Subject: Re: XSTORE Paging hierarchy. Think of XSTORE as a really highspeed buffer between main storage and real disk. If you hit a spike in paging activity (like when all your Linux guests wake up near the same time to do something cron-related), you dramatically increase the probability that the pages you want/need are in XSTOR rather than having to wait for them to come in from physical I/O. I don't really bother to attach XSTORE to a userid unless it's z/OS or maybe VSE. In most cases I've seen, those are the only guest systems that really know what to do with it, and they're doing so much of their own thing that the impact on the floor system isn't usually their big issue. On 3/4/09 1:55 PM, "Michael Coffin" < [email protected]> wrote: Hi Folks, What value is there in defining XSTORE these days? Aside from the ability to attach XSTORE to specific virtual machines, wouldn't it be best to just make it all DPA and let CP manage it? Also, assuming you aren't paging much - is attaching XSTORE to a userid going to provide a VERY noticable improvement in performance (at the expense of taking it away from all other virtual machines, of course)? -Mike "Email Firewall" made the following annotations. ------------------------------------------------------------------------------ Warning: All e-mail sent to this address will be received by the corporate e-mail system, and is subject to archival and review by someone other than the recipient. This e-mail may contain proprietary information and is intended only for the use of the intended recipient(s). If the reader of this message is not the intended recipient(s), you are notified that you have received this message in error and that any review, dissemination, distribution or copying of this message is strictly prohibited. If you have received this message in error, please notify the sender immediately. ==============================================================================
