Re: question about readonly instances

On 05/19/2011 04:33 AM, Szymon Guz wrote:
>
>
> On 18 May 2011 22:22, Ireneusz Pluta <ipluta@wp.pl
> <mailto:ipluta@wp.pl>> wrote:
>
>     W dniu 2011-05-18 13:21, Szymon Guz pisze:
>
>         Hi,
>         I've got a question about quite a strange configuration.
>         I was asked if we can have one storage, with one data directory
>         where one postgresql instance writes data, and many other
>         instances read those.
>         Is that possible without any replication and copying data?
>
>
>     Why do they think they need that?
>
>
> They've got some quite nice and huge storage and it would be nice to use
> it from many different machines running postgreses.
> Another option is Oracle which can do that.

If you're thinking of Oracle RAC: be careful. Anecdotal reports I've
heard suggest that a RAC cluster needs to be about 3 machines before it
equals the performance of a single standalone Oracle instance on same
kind of hardware. I have no personal experience with this, though, and
am under the impression that the people I've heard talking about it were
referring to multi-master setups. It's possible that single-master
setups with read-only slaves are more efficient. It's also possible that
they were just wrong. All I'm saying is that you should investigate
carefully.

--
Craig Ringer