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
