Re: TSM Server Paging: Need an AIX Paging Expert to Help
2002-09-16 09:58:59
HI,
I am having the same problem on my tsm AIX SP2 silver wide server - but
with less memory - 512M - But tsm is the only application on the box - with
180 GB from an EMC Symmetrix and the rest 300+GB from SSA disks. My Maxperm
is at the default 80% - and the server crawls like molasses all the time.
Before the EMC disks were attached - I only had a problem during my TMS
database backup. Can you suggest an appropriate % to start at?
Thanks,
Jane
%%%%%%%%%%%%%%%%%%%%%%
Jane Bamberger
IS Department
Bassett Healthcare
607-547-4750
----- Original Message -----
From: "Hamish Marson" <hamish AT TRAVELLINGKIWI DOT COM>
To: <ADSM-L AT VM.MARIST DOT EDU>
Sent: Monday, September 16, 2002 9:05 AM
Subject: Re: TSM Server Paging: Need an AIX Paging Expert to Help
> Seay, Paul wrote:
>
> >Paging is a bad thing, but why would an AIX system page (like crazy)
under
> >this configuration?
> >
> >P660-6H1 2GB Memory
> >dsmserv using 384MB
> >Swap space is 3GB an only 12% used.
> >Nothing else seems to use much memory based on a ps -efl
> >
> >An old MVS person like myself would say somehow something has a free page
> >target that is really high. iostat and vmstat seem OK.
> >
> >Any AIX gurus know the answer?
> >
> >Paul D. Seay, Jr.
> >Technical Specialist
> >Naptheon Inc.
> >757-688-8180
> >
> >
> Without seeing anything else, I'd have to say it looks like your maxperm
> setting is too high. Do you have your databases on filesystems artehr
> than raw logical volumes?
>
> AIX uses spare memory for caching filesystem information. The paging
> process is the same as that used for file IO (i.e. the VMM). If the
> system is doing lots of fileIO, then active processes can be paged out
> and that memory used for file buffers. This is (Almost always) a bad
thing.
>
> The amount of memory that can be used for file buffers is controlled by
> several settings, the most important one is maxperm. That governs the
> maximum amount of physical memory that can be used by the system for
> file buffers. The default is 80%. Calculate what amount of memory you
> require for the processes that run, and drop maxperm down till you no
> longer have to page.
>
> To change maxperm, use the vmtune command
>
> /usr/samples/kernel/vmtune -P <percentage>
>
> WARNING!
>
> Because vmtune changes the running kernel, run it first with NO
> parameters to check that you get valid numbers. If someone has put a
> copy of vmtune on the system (WIthout installing it properly. i.e.
> copied it from another system) it can get out of sync with the kernel,
> and the system will crash if you attempt to change the values. (If it's
> wrong, most of them come up as -1).
>
> Hamish.
>
>
> --
>
> I don't suffer from Insanity... | Linux User #16396
> I enjoy every minute of it... |
> |
> http://www.travellingkiwi.com/ |
>
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