Re: question about readonly instances

On 19 May 2011 04:08, Craig Ringer <craig(at)postnewspapers(dot)com(dot)au> wrote:

> On 05/19/2011 04:33 AM, Szymon Guz wrote:
>
>>
>>
>> On 18 May 2011 22:22, Ireneusz Pluta <ipluta(at)wp(dot)pl
>> <mailto:ipluta(at)wp(dot)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
>

Hi,
thanks for the answer. It is not a problem to have 3 oracle instances, in
fact there will be hundreds of them probably, but could also be hundreds of
Postgres instances :)

regards
Szymon