Thread: Load Balancing / Failover cluster

Hi,

We have to develop an application for one of our clients. We are considering using PostgreSQL as the database. However, reliablity and scaliblity are key consideration. So before we go the PostgreSQL way, I would like to be sure that it supports the following features.

1. Load balancing using more that 2 server in active-active mode. It should be transparent to the client application. We should be able to add server as and when needed as growth is still unpredictable.

2. Failover, where one server takes up the load in case of failover of a server in the active-active cluster. Loss of last uncomitted transaction is acceptable but the client application should not have to restablish connection.

Basically we are looking for feature similar to Oracle RAC (Real Application Cluster) with TAF (Transaction Application Failover).

Can somebody tell me if these features are available. If yes, where can I find some reference realted to them (how to configure, relative performance etc).

Regards

Amitabh

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Hi,

On 24 Jul 2004, Amitabh Kumar wrote:


> We have to develop an application for one of our clients. We are
> considering using PostgreSQL as the database. However, reliablity and
> scaliblity are key consideration. So before we go the PostgreSQL way, I
> would like to be sure that it supports the following features.
>
> 1. Load balancing using more that 2 server in active-active mode. It
> should be transparent to the client application. We should be able to
> add server as and when needed as growth is still unpredictable.
> 2. Failover, where one server takes up the load in case of failover of
> a server in the active-active cluster. Loss of last uncomitted
> transaction is acceptable but the client application should not have to
> restablish connection.

I suggest you to take a look at C-JDBC (Clustering JDBC),which is an open
source project for these:

http://c-jdbc.objectweb.org/ (Home page)
http://freshmeat.net/projects/cjdbc

I also suggest you to read the following white paper about c-jdbc, which
also mentions about PostgreSQL:

C-JDBC: Flexible Database Clustering Middleware
http://c-jdbc.objectweb.org/current/doc/C-JDBC_Flexible_Database_Clustering_Middleware.pdf

Regards,
- --
Devrim GUNDUZ
devrim~gunduz.org                devrim.gunduz~linux.org.tr
            http://www.tdmsoft.com
            http://www.gunduz.org

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Amitabh Kumar wrote:
 > We have to develop an application for one of our clients. We are considering
 > using PostgreSQL as the database. However, reliablity and scaliblity are
 > key consideration. So before we go the PostgreSQL way, I would like to be
 > sure that it supports the following features.
 >
 > 1. Load balancing using more that 2 server in active-active mode. It should
 >  be transparent to the client application. We should be able to add server
 > as and when needed as growth is still unpredictable.
 >
 > 2. Failover, where one server takes up the load in case of failover of a
 > server in the active-active cluster. Loss of last uncomitted transaction is
 > acceptable but the client application should not have to restablish connection.

I've recently (accidentally) found the following piece of
software (I wonder why it's not mentioned on postgresql.org):

http://www.csra.co.jp/~mitani/jpug/pgcluster/en/

It's is a modified version of PostgreSQL (i.e. a patchset)
supporting multi-master synchronous replication.  According
to the description, it might be exactly what you're looking
for.

Best regards
   Oliver

--
Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München
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and may not necessarily reflect the opinions of secnetix in any way.

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