Re: 100% failover + replication solution - Mailing list pgsql-admin

Shoaib,

I agree that PGCluster might be a better option, i dont want to go with Slony because of primary key constraints. But PGCluster is a good option, the only concerns are :

1) It might slow down the process a bit. as confirmation happens after transaction gets comitted to all the nodes.
2) Its difficult to convince, as it is an external project and if support for the same stops or future versions of postgres does not work, it might be a problem.

Can you elaborate more the way PITR for HA being used for primary and secondary servers, maybe u can light a bulb in me for me to go ahead with the approach. I like the idea of using WAL logs because its postgres internal and secondly it would be fastest way of keeping databases in sync without slowing down other servers.

Awaiting your reply.

Regards,
Moiz Kothari

On 10/30/06, Shoaib Mir < shoaibmir@gmail.com> wrote:

Hi Moiz,

If I had to choose for your case where you want to direct your selects to slave node and inserts/updates on master, I would have opted for Slony or PGCluster.

Using PITR for HA can be a good option if you want to switch between primary and secondary server, where you can store the archive files on a shared disk and place a recovery file with in $PGDATA and automate the process where it can run the process of recovery on each primary and seconday like for example 5 times a day as it all depends on the number of transactions happening on the db server. I have seen a few users doing this for routine VACUUM FULL process as a maintanence activity.

Thanks,
---------
Shoaib Mir
EnterpriseDB (www.enterprisedb.com)

On 10/30/06, Moiz Kothari < moizpostgres@gmail.com> wrote:

Shoaib,

It sure does, i saw PGCLUSTER, but 3 reasons for having a postgres specific solution.

1) If pgcluster stops further development, it would be lot more hassel when upgrading to a different version of postgres.
2) Postgres specific solution would help alot going ahead in future.
3) Also architecture of pgcluster might make things slower as it updates complete cluster before confirming the request.

There are lots of them available in market, but i think WAL solution should be available, if not then the thought process should be there going ahead. I am expecting a solution out of WAL logs. Let me know if you have any thoughts about it.

Regards,
Moiz Kothari

On 10/30/06, Shoaib Mir < shoaibmir@gmail.com> wrote:

There is this project which actually is not released yet, but something that you want to achieve :)

http://pgfoundry.org/projects/pgpitrha

Regards,
-------
Shoaib Mir
EnterpriseDB (www.enterprisedb.com)

On 10/30/06, Ben Suffolk < ben@vanilla.net> wrote:

> Guys,
>
> I have been thinking about this and wanted to see if it can be
> achived. I wanted to make a 100% failover solution for my postgres
> databases. The first thing that comes to my mind is doing it using
> WAL logs. Am attaching the diagram for which i will write more here.

While its not the solution you were looking at, have you seen
PGCluser :-

http://pgcluster.projects.postgresql.org/index.html

I have not tried it, but was looking the other week at various fail-
over type solutions and came across it. It seems to be able to do
what you want.

Ben

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