I'd be inclined to go with Rich's suggestion. While it's true that your
z/VM isn't paging much now, there will almost certainly come a time when it
will. Rather than suffering erratic response time due to paging directly to
DASD (even the Shark's cache is on the wrong end of the channel cable) at
that point, why not leave some of your memory defined as Xstore as a
preventative measure -- unless you think you need the full 8G of central
storage now.
Marty
-----Original Message-----
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On
Behalf Of Robert Payne
Sent: Tuesday, May 23, 2006 1:53 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: z/VM 5.2 on z800 with 8G of memory
Yes, but since our page rate is <1 I'm wondering if what we
may gain with 8G main would be more than lost during those
rare occasions that it does really have to page to DASD which
in this case is a shark (ESS 2105). Maybe splitting hairs.
Thanks Rich.
-----Original Message-----
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED]
Behalf Of Rich Smrcina
Sent: Tuesday, May 23, 2006 12:48 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: z/VM 5.2 on z800 with 8G of memory
z/VM still uses expanded storage for multi-tiered paging. It is suggested
to
allocate expanded storage for a smoother VM paging experience (in the event
VM actually has to do any paging).
On Tuesday 23 May 2006 12:44 pm, Robert Payne wrote:
> Since we implemented z/VM 5.2 about a month ago, I changed the memory
> configuration to 6G main and 2G xstore. With our typical workload,
> the page rate is < 1 per second. We run 2 VSE guests normally, but the
> last few weeks I've also had a 3rd (z/VSE 3.1.1 in development) one
> going and it's mostly idle. This holiday weekend I may be making some
> I/O configuration changes for the 3590 tapes that just rolled in and
> was considering (while I'm at it anyway) changing the real memory
> configuration to use all 8G for main storage for VM. All VSE use NOPDS.
> Performance has not been a problem, just thought about which might be
> better. Yes I know, my mileage may vary. :)
>
> Any opinions about memory here ?
>
> Thanks,
> Bubba
--
Rich Smrcina
VM Assist, Inc.
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