[Zope] Zope Performance with Multiple Mount Points

Brian Brinegar brinegar at ecn.purdue.edu
Mon Apr 12 14:35:29 EDT 2010

Our goal with this configuration was to limit the ability of a single
site to lock the entire database during a large transaction.

Are ZEO Server transaction locks one per storage or one per server?

If the locks are per storage rather than per server I believe we could
accomplish our goal with less servers, in which case is there an upper
limit on the number of storages a single server can reasonably handle?



Andreas Jung wrote:
> Brian Brinegar wrote:
>> We've recently moved to a Zope configuration with approximately 30
>> separate databases mounted at mount points within a main database.
>> Previously, we ran a single database which was approaching 300GB in
>> size. We chose to split the database to reduce Data.fs size. We now run
>> 30 separate ZEO Servers (on a single machine).
>> However, after switching to this configuration we've noticed some
>> performance issues.
>> Initially, after a client is restarted and builds out it's caches the
>> site runs very quickly. However as the memory usage grows the
>> performance degrades. If the client gets into swap the client
>> practically dies.
>> We had 10,000 object caches on each of the databases with 2 threads on
>> the client. 30 x 10,000 x 2 = 600,000 objects in memory. We've since
>> reduced the cache sizes to 1,000 or 30 x 1,000 x 2 = 60,000 objects.
>> This seemed to extend the life of a client between restarts.
> No idea what's running onside your system and inside your Zope - 1000
> objects seems way to small for almost any case. Also 30 ZEO servers
> seems kind of extreme. We are running similar a big applications and we
> are running with five or six ZEO servers - not 30.
> -aj
>> Generally, our client machines will hover around 97%-99% memory usage
>> and 90%-100% CPU (on a 2 CPU machine).
>> We still experience periodic performance problems and are looking for
>> any input that might help us address them.
>> Thanks for your input,

Brian Brinegar
Web Services Coordinator
Engineering Computer Network

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