replicating to a stopped server
Hello,
I have a 'strange' situation:
I need to make a replica copy of my database to a reduntant
spare
computer.
The reduntant computer is not running postgres, but postgres is
installed. The redundant computer is running in a special
run-level (I'm
talking Linux here) in which Pg is _not_ running.
When the primary computer crashes the redundant one will be
rebooted in
'normal' mode and Postgres must be started with the databases
from the
replica.
a) So... how do I replicate a database to a stopped postgres ?
b) Is it safe just to copy the /var/lib/pg/* directories to the
right
place and let Pg boot on that ?
c) I know the right tool for this should be 'pg_dump' but it
needs a
live postgres daemon running, in order to install the replica.
Is this
correct ?
d) Is it viable to start postgres directlly from the dump ? by
specifying the dump-file in the cmd line ?
thx a lot
joao
Joao Miguel Ferreira wrote:
Hello,
I have a 'strange' situation:
I need to make a replica copy of my database to a reduntant
spare
computer.The reduntant computer is not running postgres, but postgres is
installed. The redundant computer is running in a special
run-level (I'm
talking Linux here) in which Pg is _not_ running.When the primary computer crashes the redundant one will be
rebooted in
'normal' mode and Postgres must be started with the databases
from the
replica.
You could use WAL archiving, but you'll want a fairly regular
full-backup of PG's files otherwise the recovery could take a long time.
See Ch 23 of the manuals for details.
--
Richard Huxton
Archonet Ltd
On Oct 12, 2007, at 1:59 PM, Richard Huxton wrote:
Joao Miguel Ferreira wrote:
Hello,
I have a 'strange' situation:
I need to make a replica copy of my database to a
reduntant
spare
computer.
The reduntant computer is not running postgres,
but postgres is
installed. The redundant computer is running in a special
run-level (I'm
talking Linux here) in which Pg is _not_ running.
When the primary computer crashes the redundant
one will be
rebooted in
'normal' mode and Postgres must be started with the databases
from the
replica.You could use WAL archiving, but you'll want a fairly regular full-
backup of PG's files otherwise the recovery could take a long time.
See Ch 23 of the manuals for details.
Are you restricted to keep that second server in that special run-
level? If not, I'd consider using pg_standby with WAL archiving to
keep your failover server at most a handful of minutes behind.
Erik Jones
Software Developer | Emma®
erik@myemma.com
800.595.4401 or 615.292.5888
615.292.0777 (fax)
Emma helps organizations everywhere communicate & market in style.
Visit us online at http://www.myemma.com
On Fri, 2007-10-12 at 14:09 -0500, Erik Jones wrote:
On Oct 12, 2007, at 1:59 PM, Richard Huxton wrote:
Joao Miguel Ferrei
Are you restricted to keep that second server in that special run-
level? If not, I'd consider using pg_standby with WAL archiving to
keep your failover server at most a handful of minutes behind.
Well, I can consider having Pg running in that special boot mode...
I'll check your suggestion.
THX to all.
jmf
Show quoted text
Erik Jones
Software Developer | Emma®
erik@myemma.com
800.595.4401 or 615.292.5888
615.292.0777 (fax)Emma helps organizations everywhere communicate & market in style.
Visit us online at http://www.myemma.com
On Fri, 2007-10-12 at 19:59 +0100, Richard Huxton wrote:
You could use WAL archiving, but you'll want a fairly regular
full-backup of PG's files otherwise the recovery could take a long time.
See Ch 23 of the manuals for details.
Restartable recovery avoids the need to re-sync from the primary as
often as was the case with 8.1 and prior.
--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com