[Zope] Preventing Zope Spinning?

[Jonathan]

Thanks for the warning!  We haven't come across any of these 'odd errors', 
but we will get rid of our persistent caches just to be sure!


Jonathan
----- Original Message ----- 
From: "Jens Vagelpohl" <jens at dataflake.org>
To: "[Zope] Mailing List" <zope at zope.org>
Sent: Thursday, May 25, 2006 11:00 AM
Subject: Re: [Zope] Preventing Zope Spinning?


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> Persistent caches can introduce odd errors, unfortunately. They can 
> create inconsistencies between what a ZEO client thinks the database 
> state is and what the ZEO server thinks. Not recommended for  production 
> setups.
>
> jens
>
>
> On 25 May 2006, at 15:56, Jonathan wrote:
>
>> 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
>>> _______________________________________________
>>> Zope maillist  -  Zope at zope.org
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>>
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