| From: | Peter Schuller <peter(dot)schuller(at)infidyne(dot)com> |
|---|---|
| To: | David Rees <drees76(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Occasional Slow Commit |
| Date: | 2008-11-06 10:21:47 |
| Message-ID: | 20081106102147.GB70379@hyperion.scode.org |
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| Lists: | pgsql-performance |
> I also found that my write cache was set to WriteThrough instead of
> WriteBack, defeating the purpose of having a BBU and that my secondary
> server apparently doesn't have a BBU on it. :-(
Note also that several RAID controllers will periodically drop the
write-back mode during battery capacity tests. If you care about
consistently/deterministically having full performance (with
white-backed battery protected caching), you probably want to confirm
your controller behavior here.
(I've seen this on at least LSI based controllers in Dell 2950:s, and
also on some 3wares.)
--
/ Peter Schuller
PGP userID: 0xE9758B7D or 'Peter Schuller <peter(dot)schuller(at)infidyne(dot)com>'
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