[Zope] syncing two instances of zope

[Paul Winkler]

On Thu, Dec 19, 2002 at 03:12:20PM -0800, AM wrote:
> Hi,
> I have a setup where two machines are running identical instances of 
> zope and only one of them is active to the outside world via a firewall. 
> As and when one of them goes down the other is activated by the firewall 
> for the duration that the primary went down.
> 
> How do I keep these two instances in sync at all times ( mebbe a 10-15 
> min delay between syncs)??
> 
> I looked at ZSyncer but it seems I have to explicitely specify objects 
> to be synced.

Yes, you do.
Does only one of these sites get content updates,
and the other just mirrors it?
If so, i guess you could try to use rsync to sync the
one machine's ZODB to the other, but i'd be really
wary of that. For one thing, ZODB writes are *not* really
append-only, and for another you'd want to be sure that
the  mirror wasn't doing any writing of its own.
To be safe, I've heard many recommendations that
both of the zopes that you're syncing should be
either shut down, or running in read-only mode.

On a project I'm working on now, we are adding zsyncer as 
part of our content management workflow.  We administrate
content on a private server and sync to two production servers
simultaneously; that way, one production machine can fail
over to the other, and the two production machines
are always in sync with each other. (We're doing this already,
it's just that the interface for zsyncer in CMF is not
ready yet so I'm doing all the syncs "by hand").

-- 

Paul Winkler
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