Re: Syncing DBs prior to RServ replication

Just a note to everyone.  I finally managed to scrape enough time out of my
tasklist (by staying late) so I could try this out.  Besides some difficulty
with having a RedHat 7.1 / PGSQL 7.2 box on one end and a Mandrake 9.1 /
PGSQL 7.3 box on the other end, everything worked without a hitch.

Thanks for the suggestion!

On Wednesday 11 June 2003 07:51 am, Murthy Kambhampaty wrote:
> I think you'd benefit from a two-stage Rsync (this was discussed on this
> list in the past few months):
>
> 1. Rsync the $PGDATA cluster from the "hot" server to the "standby" server,
> with the postmaster running
> 2. Stop the postmaster and perform the same rsync again (this will take
> only a few seconds on how much time elapses between the completion of the
> first stage and postmaster shutdown; 5G of data should take less than 5
> minutes to Rsync over if you're running Fast Ethernet or better).
>
> Start the postmaster on both servers, and do your Rserv thing. (I don't use
> Rserv, so I haven't tested this, but it sounds like you don't need the
> servers to have identical states, so ...)
>
> Cheers,
>     Murthy
>
> >-----Original Message-----
>
> From: Michael A Nachbaur [mailto:mike@nachbaur.com]
>
> >Sent: Monday, June 09, 2003 18:25
> >To: pgsql-admin@postgresql.org
> >Subject: [ADMIN] Syncing DBs prior to RServ replication
> >
> >
> >I'm looking at syncronizing two database servers with RServ
> >(production / "hot
> >standby"), and I'm trying to figure out a way to get the
> >initial database on
> >the slave server syncronized with the master.
> >
> >Normally, I would 1) turn off all clients, 2) dump the
> >database from the
> >master, 3) restore it into the slave, 4) turn clients back on, and 5)
> >replicate regularly.
> >
> >Unfortunately I'm running the master in a production environment where
> >anything more than 5 minutes of downtime is a really "Bad
> >Thing®".  The
> >database dump is about 5G, and so leaving the master down for
> >that entire
> >time isn't possible.  Is there a recommended way for
> >performing such a "sync"
> >without any lengthy downtime?
> >
> >I'm guessing I could start my dump, and then immediately
> >afterward create the
> >replication tables in the master.  Since the dump is
> >transactional (is it?),
> >it shouldn't include the replication tables or the replication
> >"snapshot"
> >information in it's dump, and by the time I finally finish
> >importing the dump
> >in the new server, I should be able to perform the replication
> >and pick up
> >all the new / changed records since I started the DB dump.
> >
> >Will this work?  Is there a better recommended way?  Thanks.
> >
> >--
> >Michael A Nachbaur <mike@nachbaur.com>
> >
> >
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--
Michael A Nachbaur <mike@nachbaur.com>