From: Brad Nicholson <bnichols@ca.afilias.info>
To: Joshua D. Drake <jd@commandprompt.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Investigating IO Saturation
Date: Tue, 24 Jan 2006 12:03:56 -0500
Message-ID: <43D65DFC.2040107@ca.afilias.info> (raw)
In-Reply-To: <43D658D3.5070808@commandprompt.com>
References: <43D65736.9020905@ca.afilias.info>
<43D658D3.5070808@commandprompt.com>
Joshua D. Drake wrote:
> Brad Nicholson wrote:
>
>> I'm investigating a potential IO issue. We're running 7.4 on AIX
>> 5.1. During periods of high activity (reads, writes, and vacuums),
>> we are seeing iostat reporting 100% disk usage. I have a feeling
>> that the iostat numbers are misleading. I can make iostat usage jump
>> from less than 10% to greater than 95% by running a single vacuum
>> against a moderate sized table (no noticeable change in the other
>> activity).
>>
> Well that isn't surprising. Vacuum is brutal especially on 7.4 as that
> is pre background writer. What type of IO do you have available (RAID,
> SCSI?)
>
Data LUN is RAID 10, wal LUN is RAID 1.
--
Brad Nicholson 416-673-4106 bnichols@ca.afilias.info
Database Administrator, Afilias Canada Corp.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: bnichols@ca.afilias.info, jd@commandprompt.com
Subject: Re: Investigating IO Saturation
In-Reply-To: <43D65DFC.2040107@ca.afilias.info>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox