Re: Question about switchover with PG9 replication

Le 07/02/2011 09:57, Wouter D'Haeseleer a écrit :
> Question 1 : is it possible to have such a replication configuration
> with the streaming replication of PG9 (cascaded replication) ?
>
> Nope, as far as I have tested pg only has 1 master and can have a
> number of slaves, so having 2 masters is not possible.
>
The second host named master2 is a slave which has slaves too, not a
master on which you can write.
>
>
> Question 2 : All the procedures I have seen describing a switchover
> between 2 PG servers require to copy (or rsync) the database from the
> new master (old slave) to the new slave (old master).
> Is it possible to do switchover between sites (between PGMaster1 and
> PGMaster2) whithout copying all the database from the new PG master to
> the new PG slave ?
> If it is not possible yet, shall it be possible in future releases ?
>
> Nope this is not possible, pg requires to have an updates
> basebackup at the slave, this is because if you loose a lot of
> streamed wal files it is impossible for the slave to catch up and
> have consistent data.
>
>

--
Cyril SCETBON