Hi All,
I would like to know that does Postgres supports clustering concept like MySQL Clustering or Oracle RAC ?
We need to setup our server side architecture where we want a load balanced servers hitting to shared data storage, not in active/passive modes but working simultaneously. Replication is one way to create load balanced architecture but we don't want replication here. Is it any way to make a shared storage cluster for two or more postgres servers ??
Thanks in advance

Clustering

PostgreSQL is more commonly utilized in the enterprise environment so I can't see how it could NOT support clustering.

Well Postgres does indeed not support the same type of clustering as MySQL does. But most of the time a single PostgreSQL server scales a lot better than a single MySQL server, so "clustering" is usually only used for fail-over scenarios not so much for load-balancing

I've never used MySQL that much and assumed their clusters were only used for fail over and not load balancing. So you're saying basically:

MySQL Clustering = Load Balance & Fail Over
PostgreSQL Clustering = Fail Over ONLY

Is that correct?

I have never really used MySQL but that was my impression, yes.

But with 9.0 the hot standby server can also be used for queries, so you get some kind of load balancing out of the box.

But of course there are 3rd party solutions for PostgreSQL (pg-bouncer, pg-pool) that can give you load balancing as well. They are a bit cumbersome to setup though.

I've only got one PG server at work that gets backed up every hour but you're saying if I want to configure a 2nd cluster for fail over (kind of like RAID 1 mirror), I would need to use a 3rd party utility or is this native to PostgreSQL?

No, fail over support has been part of PostgreSQL since 8.0 I think

This is all explained in the manual:
PostgreSQL: Documentation: Manuals: PostgreSQL 9.0: High Availability, Load Balancing, and Replication

The key point to remember is that postgresql scales up, handling hundreds of concurrent users on the individual server much better than MySQL, which shammat mentions in Post #3. Meaning, of course, that the need for load balancing is lower with pg.

Ref Page 6 of this server comparison at Tweakers.net. The gist of the article is a real-world hardware server comparison under various levels of concurrency, but in taking a look at the results, it's quite clear that pg scales quite nicely. MySQL, not so much.

I do prefer PostgreSQL over MySQL for various reasons, but I wonder how this benchmark would look like with MySQL 5.5 as they claim that the write performance of InnoDB has been improved drastically.