| From: | Craig Ringer <craig(at)postnewspapers(dot)com(dot)au> |
|---|---|
| To: | Greg Smith <greg(at)2ndquadrant(dot)com> |
| Cc: | Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, Anton Belyaev <anton(dot)belyaev(at)gmail(dot)com>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Huge iowait during checkpoint finish |
| Date: | 2010-01-12 01:22:23 |
| Message-ID: | 4B4BCECF.5080508@postnewspapers.com.au |
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| Thread: | |
| Lists: | pgsql-general |
Greg Smith wrote:
> If the old system had a write caching card, and the new one doesn't
> that's certainly your most likely suspect for the source of the
> slowdown.
Note that it's even possible that the old system had a card with write
caching enabled, but *no* battery backed cache. That's crazily
dangerous, but does get you the speed benefits of write caching without
the need for a BBU. I only mention this to help explain a possible
performance difference - you should NEVER do this if you care about your
data.
--
Craig Ringer
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