| From: | Matthew Wakeling <matthew(at)flymine(dot)org> |
|---|---|
| To: | Fernando Hevia <fhevia(at)ip-tel(dot)com(dot)ar> |
| Cc: | 'Scott Marlowe' <scott(dot)marlowe(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: new server I/O setup |
| Date: | 2010-01-15 17:15:39 |
| Message-ID: | alpine.DEB.2.00.1001151714090.6195@aragorn.flymine.org |
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| Lists: | pgsql-performance |
On Fri, 15 Jan 2010, Fernando Hevia wrote:
> I was wondering if disabling the bbu cache on the RAID 1 array would make
> any difference. All 256MB would be available for the random I/O on the RAID
> 10.
That would be pretty disastrous, to be honest. The benefit of the cache is
not only that it smooths random access, but it also accelerates fsync. The
whole point of the WAL disc is for it to be able to accept lots of fsyncs
very quickly, and it can't do that without its BBU cache.
Matthew
--
Heat is work, and work's a curse. All the heat in the universe, it's
going to cool down, because it can't increase, then there'll be no
more work, and there'll be perfect peace. -- Michael Flanders
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