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:ib...@listserv.uark.edu] On Behalf Of David Boyes
Sent: Wednesday, March 04, 2009 11:02 AM
To: IBMVM@LISTSERV.UARK.EDU
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" <michaelcof...@mccci.com>
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
