| From: | Brad Nicholson <bnichols(at)ca(dot)afilias(dot)info> |
|---|---|
| To: | "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Investigating IO Saturation |
| Date: | 2006-01-24 17:03:56 |
| Message-ID: | 43D65DFC.2040107@ca.afilias.info |
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| Thread: | |
| Lists: | pgsql-performance |
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(at)ca(dot)afilias(dot)info
Database Administrator, Afilias Canada Corp.
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