From: Luke Lonergan <llonergan@greenplum.com>
To: Joost Kraaijeveld <J.Kraaijeveld@Askesis.nl>
To: Steve Wampler <swampler@noao.edu>
Cc: Dave Cramer <pg@fastcrypt.com>
Cc: Pgsql-Performance <pgsql-performance@postgresql.org>
Subject: Re: Performance PG 8.0 on dual opteron / 4GB / 3ware
Date: Tue, 15 Nov 2005 22:07:53 -0800
Message-ID: <BFA00CB9.13C63%llonergan@greenplum.com> (raw)
In-Reply-To: <1132084287.3250.41.camel@Panoramix>
Joost,
On 11/15/05 11:51 AM, "Joost Kraaijeveld" <J.Kraaijeveld@Askesis.nl> wrote:
> On Tue, 2005-11-15 at 12:41 -0700, Steve Wampler wrote:
>> > Joost Kraaijeveld wrote:
>>> > > If I understand correctly (I have 4GB ram):
>>> > >
>>> > > jkr@Panoramix:~/tmp$ dd if=/dev/zero of=bigfile bs=8k count=1000000
>>> > > 1000000+0 records in
>>> > > 1000000+0 records out
>>> > > 8192000000 bytes transferred in 304.085269 seconds (26939812 bytes/sec)
>>> > >
>>> > > Which looks suspicious: 26308 MB/sec???
>> >
>> > Eh? That looks more like ~25.7 MB/sec, assuming 1MB = 1024*1024 bytes.
> Oooops. This calculation error is not typical for my testing (I think ;-)).
Summarizing the two facts of note: the write result is 1/4 of what you
should be getting, and you are running 1 driver behind the firmware.
You might update your driver, rerun the test, and if you still have the slow
result, verify that your filesystem isn¹t fragmented (multiple undisciplined
apps on the same filesystem will do that).
WAL on a separate disk, on a separate controller? What is the write
performance there?
Regards,
- Luke
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To: pgsql-performance@postgresql.org
Cc: llonergan@greenplum.com, J.Kraaijeveld@Askesis.nl, swampler@noao.edu, pg@fastcrypt.com
Subject: Re: Performance PG 8.0 on dual opteron / 4GB / 3ware
In-Reply-To: <BFA00CB9.13C63%llonergan@greenplum.com>
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