Nah, mixing device types won't hurt much. as they fill, they start performing worse, and
vm balances the load to ensure optiomal performance. read about mload.
Mark Pace wrote:
I have to find the stuff, but at the z Expo we were told that mixing DASD
types in a page farm is BAAAAD! I don't remember right off hand why. Maybe
someone else can chime in while I research.
On Thu, Nov 13, 2008 at 3:28 PM, Schuh, Richard <[EMAIL PROTECTED]> wrote:
What will be the effect, other than having additional space available,
of adding five mod 9 disks to the existing page farm of 35 mod 3s? Would
there be a noticeable change in the performance of the paging subsystem?
(I suspect that any change will be less noticeable than the effects of
filling both page and spool. :-) )
Regards,
Richard Schuh
-----Original Message-----
From: The IBM z/VM Operating System
[mailto:[EMAIL PROTECTED] On Behalf Of Barton Robinson
Sent: Thursday, November 13, 2008 11:36 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Page Space
Do the math.... Number one reason for ONE outage at each new
z/linux installation is to fill up page space - guess you
were lucky and had some extra spool space (no block paging so
slow), so you luckily didn't take the outage - which makes
your servers even slower....
Schuh, Richard wrote:
Don't presume. 92G real, 10 xstore. All MDC activity is in real,
limited to 384MB. And I do not know the color of the machine :-)
Regards,
Richard Schuh
-----Original Message-----
From: The IBM z/VM Operating System
[mailto:[EMAIL PROTECTED] On Behalf Of Marcy Cortes
Sent: Thursday, November 13, 2008 10:29 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Page Space
You didn't say how much real memory you have. Presumably less than
60G
:)
You either add enough real memory or you add enough page
space to hold
them all (at less that 50% occupied. I don't think there
are miracles
available in this scenario.
Marcy
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________________________________
From: The IBM z/VM Operating System
[mailto:[EMAIL PROTECTED] On Behalf Of Schuh, Richard
Sent: Thursday, November 13, 2008 10:20 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: [IBMVM] Page Space
Yesterday, we were running a test using 17 z/TPF virtual
machines, 3GB
each. This was in addition to the normal load on the system. During
the test, which was not moving along very quickly, nothing was, I
noticed that our page packs were 100% allocated, up from the usual
10%. This stood out as a smoking gun, verified by watching the
performance improve as each of the ids in the test logged off. I
presume that this should have been expected; however, other matters
have kept us so busy that we did not do the math. I imagine
that the
one way to avoid this type of problem, we expect a peak of
approximately 150 concurrent z/TPF systems in the coming year, is a
massive injection of paging DASD. Is this the only answer
or are there
any other steps that we can take to help?
Regards,
Richard Schuh
