These are the results of my testing ZCS version 3.1 OS Edition on CentOS 4.3 (updated) on VMWare ESX server having 2 Xeon 2.8GHz, 3.5GB RAM, 100Mb network with vmware tools installed.

I have tested ZCS vs. Dovecot vs. Cyrus by filling 10 users mailboxes with 2000 mails, where 1700 of these mails were small mails from qmail mailing list and the other 300 were jokes mails (usually from several kB to several MB). There were no special tuning of the system for any of the programs, because all of them were installed via RPM and I used Posftix as MTA for dovecot and Cyrus.

Testset for IMAP testing was something like this: Courier IMAP test with 10 users. I created scripts in perl using Expect (scripts available if interested).
Testset for POP3 testing were some perl scripts using Net::Pop3 module and with simple commands.
Analysis was made with some scripts utilizing gnuplot and if you want detailed results (or scripts), PM me.

The test was made from P4 machine quite close to the server and no other virtual machines were running on VMWare ESX server at the time of the tests.

It turned out that Zimbra is quite slow compared to other two systems. We were discussing what might be the reason, but I think that only developers could tell us. At first glance we accused java for not being optimised for VMware, but there are no such explanation to be found on web. We also recorded the I/O state of the machine while in test, but the results are not analysed yet.

So here are the results:
IMAP tests: IMAP tests

to be continued in next post...