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Re: heavy swapping, not sure why

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: mark <dvlhntr(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: heavy swapping, not sure why
Date: 2011-08-31 03:05:30
Message-ID: CAOR=d=2GuWmKLXdHF880Xwnf2+hggXzdAL-6XGSkeetoMFsjxQ@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-general
On Tue, Aug 30, 2011 at 8:36 PM, mark <dvlhntr(at)gmail(dot)com> wrote:
> To the broader list, regarding troubles with kswap. I am curious to what
> others seeing from /proc/zoneinfo for DMA pages (not dma32 or normal) -
> basically if it sits at 1 or not.  Setting swappiness to 0 did not have any
> affect for us on kswap issues. Another thing I have not had time and
> resources to go work on... interested in what kernel they are running and
> what storage drivers they might be using.

Well, we had zone reclaim mode autoset to 1, and we had to turn it off
to get decent performance with postgresql.  Machine was a quad
dodecacore Magny Cours, so 48 cores with 128G RAM.  RAID controller is
an Areca 1680 with BBU, 34 15kRPM 147G SAS Seagate 15k6 drives in two
16 drive external enclosures and 2 drives in the server.

The only solution we could find for kswapd going crazy was to just
turn off swap.  Pretty sure I used a large swap file to test larger
swaps, but all that did was put off the eventual kswapd storm. It took
anywhere from one to two weeks, maybe more, and then one day you check
and your servers maxed out by kswapd.

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Next:From: Adarsh SharmaDate: 2011-08-31 05:26:55
Subject: Getting Table Names in a Particular Database
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Subject: Re: heavy swapping, not sure why

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