Re: H800 + md1200 Performance problem

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: Claudio Freire <klaussfreire(at)gmail(dot)com>
Cc: Tomas Vondra <tv(at)fuzzy(dot)cz>, pgsql-performance(at)postgresql(dot)org
Subject: Re: H800 + md1200 Performance problem
Date: 2012-04-04 16:42:14
Message-ID: CAOR=d=0mSxfZjkTQ-z5zEdMDOC9urd4fBdt7C0gp0f+hxy6bFA@mail.gmail.com
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On Wed, Apr 4, 2012 at 10:31 AM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> On Wed, Apr 4, 2012 at 10:28 AM, Claudio Freire <klaussfreire(at)gmail(dot)com> wrote:
>> On Wed, Apr 4, 2012 at 1:22 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
>>> Even with fairly late model linux kernels (i.e.
>>> 10.04 LTS through 11.04) I've watched the kswapd start up swapping
>>> hard on a machine with zero memory pressure and no need for swap.
>>> Took about 2 weeks of hard running before kswapd decided to act
>>> pathological.
>>
>> Perhaps you had some overfull partitions in tmpfs?
>
> Nope.  Didn't use tmpfs for anything on that machine.  Stock Ubuntu
> 10.04 with Postgres just doing simple but high traffic postgres stuff.

Just to clarify, the machine had 128G RAM and about 95G of it was
kernel cache, the rest used by shared memory (set to 4G) and
postgresql.

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