Re: Amazon High I/O instances - Mailing list pgsql-general

From John R Pierce
Subject Re: Amazon High I/O instances
Date
Msg-id 50525015.7000606@hogranch.com
Whole thread Raw
In response to Re: Amazon High I/O instances  (Sébastien Lorion <sl@thestrangefactory.com>)
Responses Re: Amazon High I/O instances
List pgsql-general
On 09/13/12 2:08 PM, Sébastien Lorion wrote:
> I started db creation over, this time with 16GB maintenance_work_mem
> and fsync=off and it does not seem to have a great effect. After again
> 5 hours, during index creation, disk and cpu are barely used: 95% idle
> and 2-3 MB/s writes (150 reads/s, 90 writes/s).

I've never had to set maintenance_work_mem any higher than 1gb for
plenty good enough performance.

whats the %busy on the disk ?   if you have a slow disk device (such as
a shared virtual disk), 90 write/sec may be all its good for. MB/s is
fairly meaningless when dealing with random committed writes.





--
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast




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