[Zope] Re: Fail-safe redundancy policies for Zope

[Ausum Studio]

Paul, Tres, thanks for your responses.

Has anyone in the community tried any other non-standard way to accomplish a
live backup, like to rely on a synchronization proccess auto-triggered by
parallel installations?. I'd like to go this way as the first thing to try ,
so now I'm looking for caveats from people who have alredy tried the Zsyncer
way or the likes.  :)


Ausum


----- Original Message ----- 
From: "Tres Seaver" <tseaver at zope.com>
To: <zope at zope.org>
Sent: Wednesday, October 06, 2004 4:54 PM
Subject: [Zope] Re: Fail-safe redundancy policies for Zope


> Paul Winkler wrote:
> > 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.
>
> For full QoS, ZRS out of the box would only support "warm" failover (it
> would require downing the secondary and bringing it back up as a
> primary).  We have experimented with using 'heartbeat' to automate that,
> but haven't deployed it in production.
>
> If having the appservers degrade to read-only mode on primary failure is
> a sufficient QoS, ZRS does that automatically.
>
> > 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.
>
> Right.  'heartbeat' might help there, too.
>
> Tres.
> -- 
> ===============================================================
> Tres Seaver                                tseaver at zope.com
> Zope Corporation      "Zope Dealers"       http://www.zope.com
>
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