So are you saying that if I setup the following in my recovery.conf
restore_command =.....
It will it be used only when the streaming replication falls behind more than ( wal_keep_segments ) or replication stream is not available (master goes down) ?
Thanks for your help.
On Monday, April 14, 2014 1:35 PM, Albe Laurenz <laurenz.albe@wien.gv.at> wrote:
Anupama Ramaswamy wrote:
> I would like to setup a 2 servers with streaming replication, one master and another hot standby. > I want to use the standby for read-only queries. So I want the replication lag to be as small as > possible. > So I choose streaming replication over WAL shipping. > > When the master fails, I want the standby to take over as master. So I would like minimal data loss, > if there is a streaming replication delay. > > Is it possible to setup such a way that under normal conditions the standby by replicating using > streaming replication and on failover, it uses the WAL archive for syncing up with the transactions. > Of course the WAL will be available on a shared storage volume. If this is possible, what exactly do I > need in my configuration files - postgresql.conf, recovery.conf ?
Most of this will happen automatically - WAL archives are used if recovery falls behind.
Where you will need additional software is automatic failover; you need some OS cluster software that can detect failure and automatically promote the standby.