From: Karl Denninger <karl@denninger.net>
To: Justin Graf <justin@magwerks.com>
Cc: Grzegorz Jaśkiewicz <gryzman@gmail.com>
Cc: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: raid10 write performance
Date: Tue, 22 Jun 2010 09:29:53 -0500
Message-ID: <4C20C8E1.7060306@denninger.net> (raw)
In-Reply-To: <4C20BD33.1040908@magwerks.com>
References: <AANLkTinbKXufTYhNuhNaOW2kWM-simIL3dg0uFX7Ij6g@mail.gmail.com>
<4C20BD33.1040908@magwerks.com>
Justin Graf wrote:
> On 6/22/2010 4:31 AM, Grzegorz Jaśkiewicz wrote:
>
>> Would moving WAL dir to separate disk help potentially ?
>>
>>
>
> Yes it can have a big impact.
WAL on a separate spindle will make a HUGE difference in performance.
TPS rates frequently double OR BETTER with WAL on a dedicated spindle.
Strongly recommended.
Be aware that you must pay CLOSE ATTENTION to your backup strategy if
WAL is on a different physical disk. Snapshotting the data disk where
WAL is on a separate spindle and backing it up **WILL NOT WORK** and
**WILL** result in an non-restoreable backup.
The manual discusses this but it's easy to miss.... don't or you'll get
a NASTY surprise if something goes wrong.....
-- Karl
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Cc: karl@denninger.net, justin@magwerks.com, gryzman@gmail.com
Subject: Re: raid10 write performance
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