Message-ID: <515A7E16.5080005@catalyst.net.nz>
Date: Tue, 02 Apr 2013 19:43:34 +1300
From: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
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To: Armand du Plessis <adp@bank.io>
CC: Jeff Janes <jeff.janes@gmail.com>,
	pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: Problems with pg_locks explosion
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Also it is worth checking what your sysctl vm.zone_reclaim_mode is set 
to - if 1 then override to 0. As Jeff mentioned, this gotcha for larger 
cpu number machines has been discussed at length on this list - but 
still traps us now and again!

Cheers

Mark

On 02/04/13 19:33, Armand du Plessis wrote:
> I had my reservations about my almost 0% IO usage on the raid0 array as
> well. I'm looking at the numbers in atop and it doesn't seem to reflect
> the aggregate of the volumes as one would expect. I'm just happy I am
> seeing numbers on the volumes, they're not too bad.
>
> One thing I was wondering, as a last possible IO resort. Provisioned EBS
> volumes requires that you maintain a wait queue of 1 for every 200
> provisioned IOPS to get reliable IO. My wait queue hovers between 0-1
> and with the 1000 IOPS it should be 5. Even thought about artificially
> pushing more IO to the volumes but I think Jeff's right, there's some
> internal kernel voodoo at play here. I have a feeling it'll be under
> control with pg_pool (if I can just get the friggen setup there right)
> and then I'll have more time to dig into it deeper.
>
> Apologies to the kittens for the interrupting your leave :)
>


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