I have a clustered mail server with two mailboxes with the following specs:
- R6.5.3 FP1
- Windows 2000
- Scanengine 7.510-1002 Mail Scan
- 8 MB of memory
- Real Time scan memory 5 MB
- Scheduled scan memory 5 MB
- About 450 users
- Server transactions per minute: 3000 - 4500 (during working hours).
- And a huge amount of mailbox accesses that only grows.
Technically, the statistic you refer to relates to the number of threads created while processing the messages in the mailboxes on the server. The mail.mailbox statistics are available -- as you have indicated -- when more than one mailbox have been enabled.
This statistic will, of course, grow as more mail is processed by the router.
Check your other mail.mailbox statistics (show stat mail.mailbox.* through a console) to see what the numbers are currently like for the corresponding statistic.
mail.mailbox.accessconflictsand then do some math.
The recommendation is that, should mail.mailbox.accessconflicts be greater than 2% of the mail.mailbox.accesses, then you should add an additional mail.box (increase the number of mail boxes in the server configuration document) to decrease the number of errors, hangs, conflicts and so on by the router while processing messages to increase your router's performance.
This is easy to do over an extended period of time, as both statistics will grow (transfers and conflicts) and you are able to get a better understanding of your overall mail-routing performance, rather than just basing decisions on a snapshot (take the case where a user does a mailing in the middle of the day, once every six months to 1 million clients).
By the same token, should the mail.mailbox.accessconflicts stat be minuscule compared to the mail.mailbox.accesses, then you are probably not receiving any performance improvements on your router by enabling multiple mail.box files.
This was first published in June 2005