[Zope] Fail-safe redundancy policies for Zope

[Paul Winkler]

On Wed, Oct 06, 2004 at 02:35:50PM -0500, Ausum Studio wrote:
> What are the best, or most used fail-safe redundancy practices suitable to
> Zope? More in detail, I'm working on a Zope-based system that will store the
> data inside the ZODB, and one of the design requests is that given an
> unrecoverable hardware crash, the system could continue running using a
> mirror installation with the latest backup (not later than half an hour or
> even less.)
> 
> APE looks like the way to go since it allows the use of standard backup
> software, but you may have tried other possible solutions for a problem like
> this. According to your experience how would you accomplish it?

I haven't actually implemented either of these, but:

You could spend some $$ and get ZRS from zope corp which
IIRC might let you do automatic failover without loss of service.
Not sure though.

You could also use DirectoryStorage and frequently replicate to a
backup storage server.  The backup can't actually serve to ZEO clients
as long as you're replicating to it, but you might be able to come up with
some scripts that automatically start a live storage process on
the backup if the primary fails.  
Reverting to the primary server might have to be
a largely manual process.

-- 

Paul Winkler
http://www.slinkp.com