Re: Postgresql Replication

Nareen S wrote:
> Current Setup
> I am having a Mailserver running on Postfix.For the same I had configured a
> High Availability Solution using Heartbeat and DRBD for
> replication.Thesetup is like Primary/Secondary Node Servers and all
> mails are replicated to
> secondary using DRBD.If primary server fails secondary will be up with mails
> ..
> The total number of users is 600 users,and Hardware used is Two Compaq
> servers with SCSI HDD,1 GB RAM each,
> Network-100Mbps
>
> New Planned Setup
> Now I am planning for Postgresql server in the same setup.I want to know
> will it work in the same setup.ie if I configure
> a new device in drbd can I get HA for postgresql also.If I use DRBD for
> postgresql also ,will it affects the existing setups.Finally if it is not
> possible what is the next option for this.

It *should* work as long as you don't start the PostgreSQL server on the
second machine until you are sure that the first has failed. It will
then think it is recovering from having crashed.

This is assuming that drbd doesn't mess with how fsync() works, and I
seem to remember it doesn't last time I looked.

The alternative (assuming you're using the database for user
details/routing etc) would be replication (slony/dbmirror/etc) or
perhaps even PITR depending on the rate of change of the database.

--
Richard Huxton
Archonet Ltd