> My company finally has the means to install a new database server for
> replication. I have Googled and found a lot of sparse information out
> there regarding replication systems for PostgreSQL and a lot of it
> looks very out-of-date. Can I please get some ideas from those of you
> that are currently using fail-over replication systems? What
> advantage does your solution have? What are the "gotchas" I need to
> worry about?
>
> My desire would be to have a parallel server that could act as a hot
> standby system with automatic fail over in a multi-master role. If
> our primary server goes down for whatever reason, the secondary would
> take over and handle the load seamlessly. I think this is really the
> "holy grail" scenario and I understand how difficult it is to
> achieve. Especially since we make frequent use of sequences in our
> databases. If MM is too difficult, I'm willing to accept a
> hot-standby read-only system that will handle queries until we can fix
> whatever ails the master.
> We are primary an OLAP environment but there is a constant stream of
> inserts into the databases. There are 47 different databases hosted
> on the primary server and this number will continue to scale up to
> whatever the server seems to support. The reason I mention this
> number is that it seems that those systems that make heavy use of
> schema changes require a lot of "fiddling". For a single database,
> this doesn't seem too problematic, but any manual work involved and
> administrative overhead will scale at the same rate as the database
> count grows and I certainly want to minimize as much fiddling as
> possible.
>
>
If you really need "only" need automatic failover than use DRBD + Heartbeat
somebody already mentioned. We are using this solution since 3 years now.
With DRBD replication is done at filesystem block level. So you don't
have to
bother about changes done with a DDL statement and Heartbeat will
automatically failover if one server goes down. It's really stable.
If you want MM you should give Cybercluster a try.
(http://www.postgresql.at/english/pr_cybercluster_e.html)
They offer good support and is Open Source since a few month now.
Robert
