Re: Fault Tolerant Postgresql (two machines, two postmasters, one disk array)

On Thu, May 10, 2007 at 20:43:20 -0500,
  John Gateley <gateley@jriver.com> wrote:
> Sorry if this is a FAQ, I did search and couldn't find much.
> 
> I need to make my Postgresql installation fault tolerant.
> I was imagining a RAIDed disk array that is accessible from two
> (or multiple) computers, with a postmaster running on each computer.
> (Hardware upgrades could then be done to each computer at different
> times without losing access to the database).
> 
> Is this possible?

You can't have two postmasters accessing the same data. Doing so will cause
corruption. You can have a failover system where another postmaster starts
after the normal one has stopped. But you need to be completely sure the
normal postmaster has stopped before starting the backup one.

> Is there another way to do this I should be looking at?

Depending on your needs replication might be useful.