Following many months of attempting to resolve an issue whereby incoming mail delivery was disrupted every 48 – 60 hours, I now have a functioning patch in place. Recently, I determined that the mail filter (amavis), was faulting during it’s cleanup cycle. Somehow it’s temp (working) folder is deleted, and then the process hangs. Consequently, postfix is unable to deliver mail since the filter has broken it’s connection. Thanks to monit (http://en.wikipedia.org/wiki/Monit), I was able to configure a service that verifies the temp folder status every 60 seconds, and then creates the folder with the proper user/group permissions (_amavisd:_amavisd) if it does not exist. Mail delivery is restored immediately, as the amavis process is now able to execute.
No need to watch the server logs in real-time any longer!
The amavisd version included with Mountain Lion is 2.8.0. I believe that somewhere in the modified code is an error that is triggered by a yet to be identified instruction sequence or message handling. It is certainly due to some modification I made to the server config at some point. Either way, there should be no further ‘tweaking’ required. I am now able to direct my attention back to the pure Linux mail server that will enable end users to customize their own mail filtering options. Once the configuration is tested, I can begin importing the active directory accounts, and replicating dovecot folders.
Now that I won’t have to restart the mail service – the monit solution solves the problem gracefully. Existing IMAP connections to dovecot are not disrupted, so end users are not disconnected from their mailboxes. Not only will confidence be restored, but secondary issues such as incorrect passwords entered at the mail client’s prompting will improve end user satisfaction.