Our IMAP server supports about 200 users. The operating system is FreeBSD 5.3. The users have home directories on this machine, but no shell access. There is no POP access. All user interaction is by means of IMAP and their email client (Thunderbird and Outlook with a slight advantage to Thunderbird. A small amount of Squirrelmail.) The mail is delivered into the users /var/mail mailbox using procmail. >From this point on, all movement is under the control of IMAP.
Up until about 6 months ago, the user mailboxes were traditional UNIX flat file mailboxes. Except for some severe performance issues as some of the old mailboxes approached the multi-gigabyte size, there were no problems of corruption with the old mailboxes. In September of 2007, I started converting everything into mix format. The performance of the mix mailboxes is fantastic. There have been occasional problems, however. The majority have been with corrupted .mixindex files. In the first several months, the problems were corrected as soon as they were found, usually by having the user calling to complain. Comprehensive documentation was not kept, so these incidents will not be discussed. Documentation has been kept, however, on the last three problems. On 20 February, a user's INBOX .mixindex was corrupted in the following way (two lines above and below the bad line are being shown): :000005e4:20070405104958-0400:00001370:46e6e89f:000e3fe0:0000002d:00000631: :000005e5:20070405113021-0400:000425e8:46e6e894:00000000:0000002d:000007a3: :000005e6:20070405113519-0400:0004:00000000:0000002d:615:0000002d:000005b9: :000005e7:20070405114940-0400:00003c12:46e6e894:00042f6b:0000002d:0000066a: :000005e8:20070405120232-0400:000227cd:46e6e894:00046baa:0000002d:000004f5: On 04 March, a user's "Sent Items" .mixindex was corrupted in the following way: :0000099a:20070529164149-0400:000189e3:46e813b5:00096fc4:0000002d:000001d2: :0000099b:20070529172503-0400:000004e2:46e813b5:000af9d4:0000002d:000002d5: :0000099c:23:460:000004e2:400:00003b3f:46e813b5:000afee3:0000002d:00000244: :0000099d:20070530105047-0400:00017fd7:46e813b5:000b3a4f:0000002d:000001cd: :0000099e:20070530105244-0400:0000032f:46e813b5:000cba53:0000002d:00000258: On 15 March, a user's INBOX .mixindex was corrupted in the following way: :00006a73:20080204085837-0500:0000930a:47a75a39:0003713c:0000002d:0000060f: :00006a74:20080204092942-0500:0005453c:47a75a39:00040473:0000002d:000006f4: :00006a2942-0500:0093605-0500:00000604:47a75a39:000949dc:0000002d:00000542: :00006a76:20080204093739-0500:0000a6d0:47a75a39:0009500d:0000002d:00000736: :00006a77:20080204094407-0500:00001ff1:47a75a39:0009f70a:0000002d:0000076f: No system or power problems. Three different users. Two physical disc drives. In at least two of the cases, the mangled index line was pointing to fairly old email. I strongly suspect that the email in question was not being looked at or deleted. The bad index line in each case was fixed by restoring a clean version of the line from a backup. Everything then worked normally. The mixrbld was first attempted in the first two cases. The very large number of "UID ran backwards" messages in the first two cases, 333 and 351, eliminated confidence in the rebuild and prompted the restoring of the bad line from a backup. In the third, recent, case, a mixrbld was tried as an experiment after restoring the bad line from a backup. In this case, no error messages at all. Two different IMAP versions were in use during the above mentioned problems. The first two happened when the release version of 2006k was being used. The last problem happened about ten days after version 2007 was installed. Any ideas? Dennis R. Kolpanen Senior Staff Engineer Kearfott Guidance & Navigation _______________________________________________ Imap-uw mailing list [email protected] https://mailman1.u.washington.edu/mailman/listinfo/imap-uw
