Hello fellow listmembers,
We switched to a new version of the cyrus imapd (version 2.0.12) and i think we have
encounted the 'locking problem' that is being discussed here.
What we are seeing here is that it takes a long while for the greetings to show even
after the connection has been established. A whole lot of tracing and debugging turned
up that the process is waiting to get access to the mailboxes.db (and related files
like __db* and log.*). Carefull reading and backtracking through the sourcecodes show
that the problem probably is located in the db3 lib somewhere. Following is a piece of
the strace:
select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
open("/var/imap/db/log.0000000002", O_RDWR|O_CREAT|O_LARGEFILE, 0644) = 5
fcntl(5, F_SETFD, FD_CLOEXEC) = 0
_llseek(5, 9426640, [9426640], SEEK_SET) = 0
write(5, "\225\326\217\0a\316\"E;\0\0\0\215\0\0\0~5\0\200\0\0\0\0"..., 59) = 59
fsync(5) = 0
After adding some debug code in the pop3d we found out that the problem has to be
somewhere in the mboxlist_open function (mboxlist.c:1707) most likely in the DB->open
call. I suspect that the select in the strace is called by the function __os_sleep in
the sleepycat DB code.
We tried several things with amounts of prespawed processen and limiting the amount of
concurrent lmtpds etc. The best effective was disabling postfix completely. Everything
ran smoothly, unfortunately it is not really an option. Possibly the problem is
related to the lmtpd code somehow. By the way, the proposed 'singeinstancestore'
solution did not change anything here.
I hope this information is helpfull to anyone who is researching this problem. If
anyone has made any progress in solving this problem i would greatly appreciate a
posting on the list or to private email. I have to make a descision whether we keep
trying to solve this problem or downgrade to the old mailserver again.
For the record, our setup:
hardware:
Compaq DL380
512Mb mem
Dual-PIII 933
6x18.2 Gb disks (smartarray 2x3disks in raid5)
software:
RedHat 6.2
Linux 2.4.2(smp)
Sleepycat DB 3.2.9
Cyrus IMAPD 2.0.12
Cyrus SASL 1.5.24
PostFix 19991231-pl13
Regards,
Hugo
--
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"That i'm paranoid doesn't mean they aren't out to get me!"
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Hugo Trippaers (HT2-6BONE) ISION Internet BV
System Engineer (RHCE) http://www.ision.nl
[EMAIL PROTECTED]
