From: Bruce Momjian <bruce@momjian.us>
To: Shaun Thomas <sthomas@optionshouse.com>
Cc: Reza Taheri <rtaheri@vmware.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: PGSQL, checkpoints, and file system syncs
Date: Wed, 9 Apr 2014 12:42:23 -0400
Message-ID: <20140409164223.GB8686@momjian.us> (raw)
In-Reply-To: <0683F5F5A5C7FE419A752A034B4A0B97978B5EBE@sswchi5pmbx2.peak6.net>
References: <66CE997FB523C04E9749452273184C6C19DAC05908@exch-mbx-113.vmware.com>
<0683F5F5A5C7FE419A752A034B4A0B97978B5EBE@sswchi5pmbx2.peak6.net>
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On Tue, Apr 8, 2014 at 02:00:05PM +0000, Shaun Thomas wrote:
> So if you are on a 1GB RAID card, set it to 1GB. Once you have 1GB
> of dirty memory (from a checkpoint or whatever), Linux will begin
> flushing.
>
> This is a pretty well-known issue on Linux systems with large amounts
> of RAM. Most VM servers fit that profile, so I'm not surprised it's
> hurting you.
Agreed. The dirty kernel defaults Linux defaults are too high for
systems with large amounts of memory. See sysclt -a | grep dirty for a
list.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
--
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To: pgsql-performance@postgresql.org
Cc: bruce@momjian.us, sthomas@optionshouse.com, rtaheri@vmware.com
Subject: Re: PGSQL, checkpoints, and file system syncs
In-Reply-To: <20140409164223.GB8686@momjian.us>
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