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Date: Wed, 28 Nov 2012 17:49:12 +0300
Message-ID: <CAE-mSOLcc-USkCZqsiCFsp2SqJ7VPDdkkCHRCxP=8hSg=gAjdw@mail.gmail.com>
Subject: Re: Performance Difference on UFS and ZFS
From: Sergey Kandaurov <pluknet@gmail.com>
To: =?UTF-8?B?TWV0aW4gRMO2xZ9sw7w=?= <metindoslu@gmail.com>
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On 28 November 2012 12:35, Metin D=C3=B6=C5=9Fl=C3=BC <metindoslu@gmail.com=
> wrote:
> Hi -
>
> I installed PostgreSQL 9.1.6 on FreeBSD 9.0-RELEASE, and compared ZFS
> to UFS. I also made sure all data easily fit into memory, ran some
> sequential scan queries on the database.
>
> Query run times on UFS were 100-200% slower than those of ZFS. This
> was intriguing as all data came from memory. What could be causing
> such a large performance difference?

Hi Metin D=C3=B6=C5=9Fl=C3=BC!

That's interesting. Can you please share your settings?
Hardware configuration, system tuning (sysctl, zfs), PostgreSQL settings,
data access pattern (read/write ratio), and how you measure performance
would be a good start.

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wbr,
pluknet