Re: Reliability of WAL replication

Marc,

On Tue, 2007-10-23 at 13:58 +0200, Marc Schablewski wrote:
> We had some corrupted data files in the past (missing clog, see
> http://archives.postgresql.org/pgsql-bugs/2007-07/msg00124.php) and are
> thinking about setting up a warm standby system using WAL replication.
> 
> Would an error like the one we had appear in WAL and would it be
> replicated too? Or is there some kind of consistency check, that
> prevents broken WAL from being restored?

Here we had WAL based replication in place some time ago, and the result
are somewhat mixed: in one case the corruption was replicated, other
times it was not... I guess it has to do with where the corruption
occurred, and I have a feeling the first case (corruption replicated)
was some postgres corner case reacting badly on kill -9 and alike, the
second case (corruption not replicated) was file system corruption. I
didn't run WAL based replication for a while, so I don't know what have
changed in it lately...

Cheers,
Csaba.