Re: Cyrus-imapd 2.4.17: processes stick on mailbox locking resulting in total mailsystem failure
John Wade <[email protected]>
| Newsgroups | gmane.mail.imap.cyrus |
|---|---|
| Organization | Oakton Community College |
| Message-ID | <[email protected]> |
Without running gdb on the process, I have no idea, but your problem sounds similar to something we hit a very long time ago: See https://www.oakton.edu/user/3/jwade/cyrus/Readme.html In our cases, the problem was the imapd process that was holding the lock was trying to obtain a second lock on the same file. What does a stack trace look like on the imapd process that is holding the lock? It would appear the lock process has changed since I last looked at this, so this may not be a help at all. Good luck, John On 12/13/2018 5:21 AM, Ivan Kuznetsov wrote: > Hello > > We had a company mail server under Oracle Linux 6 (a clone of RHEL6) > with cyrus-imapd 2.3.16 working for years w/o problems. There are >9M > messages in ~9500 mailboxes in two partitions. Daily mail traffic is > 20-50K messages. > > Some weeks ago we migrated the server to a new one under Oracle Linux > 7 with cyrus-imapd 2.4.17 (cyrus-imapd-2.4.17-13.el7.x86_64 rpm) and > now have problem. Some times a week one of imapd processes locks an > "INBOX" mailbox with corresponding /var/lib/imap/lock/user/<user>.lock > file and does not unlock it anymore. Other imapd processes trying to > access this mailbox sticks waiting to obtain the lock. The bigger > problem is that lmtpd processes trying to deliver new mail to this > mailbox hangs too. The number of lmtpd processes is limited > (maxchild=32) to limit the server load, so free lmtpd pool become > empty after a time, and mail delivery stopsto all the mailboxes. MTA > (postfix) mail queue blows up quickly > > Example lsof output: > > lmtpd 8182 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 8183 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 8187 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 8771 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 8834 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 9123 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 9631 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 10343 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 10437 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 11411 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 11413 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > lmtpd 11506 cyrus 18uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > > [root@hippo4 bin]# lsof /var/lib/imap/lock/user/smilovsky.lock | grep > '^imapd' > imapd 9132 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > imapd 9154 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > imapd 10311 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > imapd 10746 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > imapd 11843 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > imapd 12059 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > imapd 21885 cyrus 19uR REG 249,0 0 202944402 > /var/lib/imap/lock/user/smilovsky.lock > > In this case the root cause imapd process is 21885. strace shows that > the process waits on a futex forever: > > [root@hippo4 bin]# strace -tt -f -p 21885 > strace: Process 21885 attached > 13:07:28.264713 futex(0x7f6dcc5ac760, FUTEX_WAIT_PRIVATE, 2, > NULL^Cstrace: Process 21885 detached > <detached ...> > > Killing the process frees the lock, all the other stuck processes runs > and the problem disappears in a few seconds. > > Investigation shows that this process has a long-term connection from > a user MUA (Thunderbird) and deletes mail messages time-to-time. This > may be a Thunderbird 'filter' thread > > [root@hippo4 bin]# grep 'imap\[21885\]' /var/log/maillog > [...] > Dec 13 09:59:11 hippo4 imap[21885]: starttls: TLSv1.2 with cipher > DHE-RSA-AES256-SHA (256/256 bits new) no authentication > Dec 13 09:59:11 hippo4 imap[21885]: login: thunder.solvo.ru > [172.16.85.69] smilovsky CRAM-MD5+TLS User logged in > SESSIONID=<hippo.solvo.ru-21885-1544684350-1> > Dec 13 09:59:11 hippo4 imap[21885]: client id: "name" "Thunderbird" > "version" "52.5.2" > Dec 13 09:59:11 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 09:59:12 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 09:59:12 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 09:59:12 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 10:01:45 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 10:01:53 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 10:03:17 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 10:09:06 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > Dec 13 10:09:19 hippo4 imap[21885]: Expunged 1 messages from > user.smilovsky > > Problem is sporadic, I didn't see any correlation with server load, > time of day, user name and so on > > Removing "maxchild=" parameter for lmtp just delay the final as the > server system resources are limited. Now I wrote a patrol script > counting locks and killing imapd if locks number is growing up. The > trouble is I can't reliably determine the root cause imapd and kill > them one-by-one > > Any ideas more? > > Ivan Kuznetsov, SOLVO ltd > ---- > Cyrus Home Page: http://www.cyrusimap.org/ > List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/ > To Unsubscribe: > https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus ---- Cyrus Home Page: http://www.cyrusimap.org/ List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/ To Unsubscribe: https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus