2009/5/14 Dganit David <dgani...@puresight.com>: > We are planning a web application that saves the data of up to 1,000,000 > users. > > I would like to know the limitation of zodb. > > Currently we are using ClientStorage with zeo,
In my experience building a large scale application, ZEO did not scale with my application in the way that I had hoped. It worked great with a few hosts accessing the ZEO server in parallel, but when scaled up the ZEO server itself quickly became a bottleneck which had to be designed around. The thing that surprised me was that the server itself became the bottleneck with only 4 hosts active - it obviously depends on the access patterns of your application. A single ZEO server may not serve the needs of 1 million users if you have a large number accessing the application concurrently, so I suggest that you think about multiple servers, replication, and dividing the data itself up to enabling parallel distributed access before starting to code the application. And ensure that you have a test suite that will simulate the large scale requirements from the beginning. The only other limitation was packing - when the database grew to several GB it became a lengthy process to pack, and eventually packing became impossible due to the large memory requirements (I posted to the list at the time, and discovered that this was expected behaviour). Once you understand that ZEO is not some magic solution, and that you still need to think about all the usual database problems, then things will fall into place quite easily ;-) _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev