Re: Hardware suggestions for high performance 8.3

25 jun 2008 kl. 17.45 skrev Greg Smith:

> On Wed, 25 Jun 2008, Henrik wrote:
>
>> Would you turn off fsync if you had a controller with BBU? =)
>
> Turning off fsync has some potential to introduce problems even in
> that environment, so better not to do that. The issue is that you
> might have, say, 1GB of OS-level cache but 256MB of BBU cache, and
> if you turn fsync off it won't force the OS cache out to the
> controller when it's supposed to and that can cause corruption.
>
> Also, if you've got a controller with BBU, the overhead of fsync for
> regular writes is low enough that you don't really need to turn it
> off. If writes are cached the fsync is almost free.
Thanks for a thoroughly answer. I guess I wont be turning of fsync. :)

Thanks Greg!

>
>
> --
> * Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com
> Baltimore, MD
>
> --
> Sent via pgsql-performance mailing list (pgsql-performance(at)postgresql(dot)org
> )
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-performance