[Zope] Preventing Zope Spinning?

[Jonathan]

How about setting up persistent caches for your zeo clients, so that when 
the zeo server goes down you save some cache-reloading time when it 
restarts?


Jonathan


----- Original Message ----- 
From: "Brian Brinegar" <brinegar at ecn.purdue.edu>
To: <zope at zope.org>
Cc: "David S Carmichael" <carmicha at ecn.purdue.edu>; "Andrew T Sydelko" 
<sydelko at ecn.purdue.edu>; "Christopher N Deckard" <cnd at ecn.purdue.edu>
Sent: Thursday, May 25, 2006 10:49 AM
Subject: [Zope] Preventing Zope Spinning?


> The majority of the Purdue University Engineering web presence is
> provided via a cluster running ZEO. We offer hosting for every school,
> department, faculty, staff, and student in the College. Because of this
> we have a large number of content maintainers/developers on our system.
> We are running into problems with users writing bad code which spins or
> uploading huge files which seems to tie up the database for long periods
> of time.
>
> We end up in a situation where something will spin a client and a user
> will repeatedly resubmit the request until all of our zeo clients are
> spinning. Our clients are eventually killed, usually manually, and
> quickly come back up. We drop the zeo cache on a restart to improve
> startup speed, so when the clients do come back up we have 100% cache
> misses and the zeo server gets pounded resulting in slow performance
> until the client caches repopulate.
>
> Occasionally we can track down the offending URL and correct the
> problem, sometimes we cannot.
>
> Perhaps these issues will be addressed in future versions of Zope, we
> are currently running Zope 2.6.4
>
> What I would like is some sort of timeout for requests, however I do not
> want to punish users with slow connections. Perhaps a way to kill off a
> specific request that is consuming excessive resources, without killing
> the entire client.
>
> Below is some information on our setup:
>
> 1 zeo server (Solaris)
>  - 82 gig datafs
>  - transaction time out of 120 seconds
>
> 2 load balanced zeoclients (Linux)
>  - 2 gig zeo cache
>  - Database Cache 30000 objects
>  - 4 threads
>
> 2 failover apaches (Linux)
>  - using pydirector for load balancing
>
> We are receiving appoximately 1 million hits per day, which from what
> I've read is not all that much. We probably have a higher number of DB
> writes than usual because of the number of developers/maintainers. Can
> anyone make suggestions for providing a more stable environment?
>
> Thank you,
> Brian Brinegar
> Web Systems Developer
> Engineering Computer Network
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