On Tue, 2007-01-09 at 07:36, dcrespo wrote:
> Hi everybody,
>
> I have two computers with a Postgres Database each. I want one of them
> to be the replica of the other one; let's say I want a Master to Master
> replication in order to use either one (but only one at a time) as the
> main database: in case of failure, switch. The ideal synchronization
> way would be Synchronous. However, these two computers are going to be
> next to each other, so the asynchronous synchronization would be fast
> enough (I don't really know. Can you tell so?) for the case synchronous
> sync is not available.
>
> What I have found so far is Daffodil and Slony-I. Daffodil's name
> doesn't even appear in Postgresql.org, which is not the case for
> Slony-I. So there's a big point in favor to Slony-I.
>
> Has anybody researched on this that can point me in the right
> direction?
Possibly. Depending on your biz requirements, you may be better served
with a hot failover setup, where both machines can mount the same
storage array and if the primary server fails, the secondary server
mounts its partitions and starts up postgresql, and takes over its IPs
etc...
There are hazards with this kind of setup, because if two postmasters
run on the same data store it will corrupt it beyond repair, etc...
slony works well for what you're talking about, but you'll need to come
up with a switchover plan that meets you needs.
You could use possibly use pgpool as long as its caveats aren't a show
stopper (can't insert with random, individual inserts with things like
now() might be a little different, insert order might not be the same on
both machines, etc...
I haven't used daffodil, but have heard of it.
There's also c-jdbc and a few others.