Re: Investigating IO Saturation

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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