Re: Two identical systems, radically different performance

From: Claudio Freire <klaussfreire(at)gmail(dot)com>
To: Craig James <cjames(at)emolecules(dot)com>
Cc: Evgeny Shishkin <itparanoia(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Two identical systems, radically different performance
Date: 2012-10-08 22:50:30
Message-ID: CAGTBQpaoMLASfgTn-fufwou5-Lu6AybsGfi9a7JHeZZaeL+u6g@mail.gmail.com
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On Mon, Oct 8, 2012 at 7:48 PM, Craig James <cjames(at)emolecules(dot)com> wrote:
>> > # blockdev --getra /dev/sdb1
>> > 256
>>
>>
>> It's probably this. 256 is way too low to saturate your I/O system.
>> Pump it up. I've found 8192 works nice for a system I have, 32000 I
>> guess could work too.
>
>
> But again ... the two systems are identical. This can't explain it.

Is the read-ahead the same in both systems?

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