[Zope] Static fail-over

Chris McDonough chrism@zope.com
Mon, 21 Jan 2002 19:48:41 -0500


Linux Virtual Server works well also as a load balancer.  Additionally,
Toby Dickenson's recent patch for Zope that allows it to peer with Squid as
an ICP server (http://www.zope.org/Members/htrd/icp) is a really interesting
thing; it allows for easy failover at the app level as well as rudimentary
balancing at the IP level.  In comparison, LVS requires that you poll each
Zope behind the balancer every so often if you want to detect a failure and
react, and unlike any of the fancy $30k load balancers it doesn't look at
HTTP response codes to decide if a server returning a "503" error for
instance can be taken out of rotation.  Zope as an ICP peer has this
built-in because it takes the first nonerror response it gets from any Squid
peer.

----- Original Message -----
From: "Anthony Baxter" <anthony@interlink.com.au>
To: "Terry Hancock" <hancock@anansispaceworks.com>
Cc: <zope@zope.org>
Sent: Monday, January 21, 2002 7:18 PM
Subject: Re: [Zope] Static fail-over


> >>> Terry Hancock wrote
> > I have a Zope site which I'm doing a lot of development
> > on, and all internal safeguards aside, I feel there's a
> > significant chance of wrecking Zope in the process. Then
> > it might take anywhere from hours to days to get it back
> > up again.
>
> Aside from making sure you have a sane development and
> deployment process, you could consider using a load balancer,
> set up to point to the primary (development?) server normally,
> and switching it to a backup one when things fail. There's
> a bunch of hardware or software ones - I've used both. Hardware's
> better, obviously, but you could consider something like the
> tool 'balance' from balance.sf.net
>
> Anthony
>
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