[Zope] Is ZEO Useful

[Mark Gibson]

Thank you for your insights.  I have a much better understanding of ZEO
now.

Mark

> 
> Your performance will degrade if you do this; however, you get the benefit
> of being able to run a second Zope instance (either a full-blown instance,
> or a maintenance application using Zope.app() in a python automation script
> - useful for backup, cron jobs, etc); for example, we build and tear-down
> tempoary Zope instances to make changes to content in the odb over ZEO, and
> any memory leaks or other problems from such changes die along with the
> temporary Zope instance.  Doing work out-of-process like this also
> integrates better with cron jobs.
> 
> So, in summary, on a single box+cpu your reliablity stays the same, you
> performance likely goes down (a little bit), but you gain some flexibility
> in being able to have multiple Zope processes access the odbject database
> without contention.  On a setup with multiple boxes (or multiple CPUs if you
> have CPU affinity guaranteed), you will get increased performance as well.
> 
> ZEO's main advantages are in scaling out.  For increased reliablity with
> ZEO, you need multiple nodes in a cluster of boxes running Zope/ZEO-client
> instances, and the ability to load-balance between them and take dead-nodes
> offline.  For increased availability on the ZEO storage server, you need to
> replicate to multiple ZEO storage servers (which you can do with
> DirectoryStorage - http://dirstorage.sf.net).
> 
> You still want to run a proxy server in front of Zope in a production
> environment (Apache or Squid, I prefer Squid) to get better security and
> performance from page caching.  ZEO works well alongside this, not as a
> replacement for this type of setup (in fact if you have multiple nodes, Zope
> 2.6+ supports ICP, which will allow Squid to appropriately load balance a
> bunch of ZEO client nodes).
> 
> Hopefully this helps.
> 
> Sean
> 
> -----Original Message-----
> From: Mark Gibson [mailto:mark@dimensional.com]
> Sent: Wednesday, January 15, 2003 3:08 PM
> To: zope@zope.org
> Subject: [Zope] Is ZEO Useful
> 
> 
> 
> Is ZEO useful in a single-processor environment?  Does ZEO provide any 
> performance enhancement, or increased reliability over simply running 
> the apache in front of Zope?
> 
> 
> 
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