From: Hell, Robert <Robert.Hell@fabasoft.com>
To: Ivan Voras <ivoras@geri.cc.fer.hr>
To: pgsql-performance@postgresql.org
Subject: Re: Looking for bottleneck during load test
Date: Mon, 7 Apr 2008 22:12:23 +0200
Message-ID: <B710F3299F04664DB6B37C258FDEEB94015F1CD6@FABAMAIL.fabagl.fabasoft.com> (raw)
In-Reply-To: <ftd4ic$38k$1@ger.gmane.org>
References: <B710F3299F04664DB6B37C258FDEEB94015F1BA1@FABAMAIL.fabagl.fabasoft.com>
<ftd4ic$38k$1@ger.gmane.org>
I tried different other tools for random IO (including a self written one which does random lseek and read).
This tool, started during one of our tests, achieves 2 iops (8k each).
Started alone I get something about 1,500 iops with an avg latency of 100 ms.
We are using SAN (EMC CLARiiON CX 300) - are those ~7 MB/s really our bottleneck?
Any other tuning ideas?
Regards,
Robert
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Ivan Voras
Sent: Montag, 07. April 2008 14:38
To: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Looking for bottleneck during load test
Hell, Robert wrote:
> We have a PostgreSQL 8.2.7 database (~230 GB) running on a machine with 8 Intel Xeon Cores and 32 GB RAM (64-bit Linux 2.6.18). Data is stored on an EMC² CLARiiON on RAID 1/0 (8 x 146 GB 15k rpm).
> When we do random I/O with a small test tool (reading random 8k blocks from big files in 200 threads) on the disk we retrieve data with about 25 MB/s.
How do you test random IO? Do you use this utility:
http://arctic.org/~dean/randomio/ ?
If not, try using it, with same parameters. It might be that the latency
is destroying your performance. Do you use NFS or are you accessing the
storage as SAN?
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To: pgsql-performance@postgresql.org
Cc: Robert.Hell@fabasoft.com, ivoras@geri.cc.fer.hr
Subject: Re: Looking for bottleneck during load test
In-Reply-To: <B710F3299F04664DB6B37C258FDEEB94015F1CD6@FABAMAIL.fabagl.fabasoft.com>
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