| From: | "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com> |
|---|---|
| To: | Brad Nicholson <bnichols(at)ca(dot)afilias(dot)info> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Investigating IO Saturation |
| Date: | 2006-01-24 17:09:18 |
| Message-ID: | 43D65F3E.9040107@commandprompt.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Brad Nicholson wrote:
> 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.
How many disks?
>
>
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