Re: DRDB?

> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Martin Fandel wrote:
> >> is DRDB (http://www.drbd.org/) a recommended
> replication-solution for
> >> PostgreSQL? I asked some PostgreSQL-People and DRDB-People on the
> >> Linux-Tag in germany. But I'm not very assured about this solution.
>
> > Uh, we really don't _recommend_ replication solutions.  However, I
> > will say I have heard of Slony, but never of DRDB.  It seems DRDB
> > replicates the file system blocks to another machine.

(Um, Bruce, we talked to Alan Robertson about this in Copenhagen a
couple of months back. So you've certainly *heard* of it :P)

> I have not probed further than the site's top page, but
> unless DRBD offers some pretty strong guarantees about
> physical write order on the master being duplicated on the
> slave, it won't work reliably for Postgres.

From what I've heard, it does guarantee this. I think it requires you to
put all your stuff on the same DRBD device (no special device for WAL).
But I'm not 100% sure on this.

For example, DB2 is supported on these devices. I would assume they have
the same requirements as postgresql in this case. (See
ftp://ftp.software.ibm.com/software/data/pubs/papers/db2halinux.pdf)

//Magnus