Thread: Desaster Recovery from failover using SLONY-I

Desaster Recovery from failover using SLONY-I

From
Peter Hausmann
Date:
Hi,

After a node is dropped due to failover, it takes days to recover the
database, because it is build up from scratch.

We would prefer another approach:
Make an Online Backup of the Provider database.
The provider database continues writing new data and the Slony-Logs.
The Backup is restored to the failed system.
The slony cluster is dropped from the restored system
and the system is defined as Slony-subscriber.
How can we setup this system to recover from the status of the backup time?

Thank you for any hint.

--
Mit freundlichen Gruessen / With best
regards

Dipl.-Inform.
Peter Hausmann

DSA Daten- und Systemtechnik GmbH
Pascalstrasse 28
D-52076 Aachen
Germany

Phone:    +49 (0) 2408 / 9492- 779
Fax:      +49 (0) 2408 / 9492- 92




Re: Desaster Recovery from failover using SLONY-I

From
Andrew Sullivan
Date:
On Wed, May 30, 2007 at 12:57:55PM +0200, Peter Hausmann wrote:
> Hi,
>
> After a node is dropped due to failover, it takes days to recover the
> database, because it is build up from scratch.

This is from Slony?  You know that that's a built-in limitation, and
that the preferred method is switchover, right?  Failover should be
the last result.  (Also, you'll get better results if you discuss
this on the slony list.)

> We would prefer another approach:
> Make an Online Backup of the Provider database.
> The provider database continues writing new data and the Slony-Logs.
> The Backup is restored to the failed system.
> The slony cluster is dropped from the restored system
> and the system is defined as Slony-subscriber.
> How can we setup this system to recover from the status of the backup time?

Slony knows nothing about the WAL-archiving backup method.  When you
subscribe a datbaase, it automatically drops and recreates the target
from scratch.  There has been some discussion of how to improve that,
but AFAIK nobody has written the support for it yet.

A

--
Andrew Sullivan  | ajs@crankycanuck.ca
A certain description of men are for getting out of debt, yet are
against all taxes for raising money to pay it off.
        --Alexander Hamilton