on. Since th
en
this guest runs in the 40-50% range vs the 90-80%. What I am unable to
understand is why did one linux guest 'swapping' cause the IFL to be
totally consumed?
NOTE: VM worked great no other guests were effectted to the point user's
complained.
Just a guess till the experts chime in:
Linux disk I/O activity requires more CPU time than traditional Z
Operating systems - so when one guest starts driving 5000 I/O ops per
second to the swap device ( FBA mode vdisk in my case ) that in itself
consumes a big chunk of CPU. Then there's the
The last time I looked at the cost of swap to vdisk, at 1,000 per
second, used 10% of an 890 processor. It's very hard to constrain a
system to swap this much, this was in the lab pushing limits not
normally pushed. With z10 IFL significantly faster, swapping to vdisk
would not be a
buy you more z memory!
Regards
-Original Message-
From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On
Behalf Of Robert J Brenneman
Sent: Wednesday, January 28, 2009 9:57 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Linux Guest 'swapping'
Just a guess till the experts chime
this issue, and as a result over commits
can be much higher.
David Kreuter
From: The IBM z/VM Operating System on behalf of Barton Robinson
Sent: Wed 1/28/2009 10:36 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: [IBMVM] Linux Guest 'swapping'
The last time I
--
*From:* The IBM z/VM Operating System on behalf of Barton Robinson
*Sent:* Wed 1/28/2009 10:36 AM
*To:* IBMVM@LISTSERV.UARK.EDU
*Subject:* Re: [IBMVM] Linux Guest 'swapping'
The last time I looked at the cost of swap to vdisk, at 1,000 per
second, used 10% of an 890 processor. It's very hard
Oracles, others with few huge Oracles, and
both work really well.
Unlike WAS environments.
David
From: The IBM z/VM Operating System on behalf of Mary Anne Matyaz
Sent: Wed 1/28/2009 12:04 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: [IBMVM] Linux Guest 'swapping
On 1/28/2009 at 9:57 AM, Robert J Brenneman bren...@gmail.com wrote:
Just a guess till the experts chime in:
Linux disk I/O activity requires more CPU time than traditional Z
Operating systems - so when one guest starts driving 5000 I/O ops per
second to the swap device ( FBA mode vdisk
Mark Post wrote:
My experience isn't that it's the CPU cost of the paging I/O. It's more that
Linux, like any other virtual storage operating system, can get into a
thrashing mode, and all the kernel is doing is lots and lots of memory
management. The system runs at 100% busy, and nothing
.
-Original Message-
From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On
Behalf Of Mark Post
Sent: Wednesday, January 28, 2009 9:26 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: [IBMVM] Linux Guest 'swapping'
On 1/28/2009 at 9:57 AM, Robert J Brenneman bren...@gmail.com
On 1/28/2009 at 1:11 PM, Jack Woehr j...@well.com wrote:
-snip-
Linux on workstations and servers is not easy to push over the brink into
thrashing.
Not hard at all. Just put 20 pounds of workload into a 10pound bag, which is
exactly what happens on System z as well.
Mark Post
Operating System [mailto:ib...@listserv.uark.edu] On
Behalf Of Marcy Cortes
Sent: Wednesday, January 28, 2009 2:34 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Linux Guest 'swapping'
That's been my experience as well.
You may want to look at the vm.swappiness setting. We changed it from
60 to 20
...@listserv.uark.edu] On
Behalf Of Martin, Terry R. (CMS/CTR) (CTR)
Sent: Wednesday, January 28, 2009 12:02 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: [IBMVM] Linux Guest 'swapping'
Hi Marcy,
Forgive my ignorance but what is the vm.swappiness setting?
Thank You,
Terry Martin
Lockheed Martin - Information
...@listserv.uark.edu] On
Behalf Of Marcy Cortes
Sent: Wednesday, January 28, 2009 3:08 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Linux Guest 'swapping'
It's a kernel setting. Googling provided this definition:
Swappiness is a kernel knob (located in /proc/sys/vm/swappiness) used
to tweak how
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