Hi there! I'm using Dovecot 1.0.7 in RHEL 5.4 64bits as a IMAP/POP3 server. Dovecot authenticates users against an AD server via kerberos (pam configuration) and clients connect to it via IMAPs and POP3s with SSL. Webmail is in localhost and connects locally also with SSL. All is fine and people use the email server normally and with no problems. But, I have noticed that dovecot hangs sometimes. Usually twice a day somewhere between 09:40 and 10:00 a.m and in the afternoon at about 3:00 p.m. The problem starts when webmail takes long to authenticate and show folders and stuff. After a while it times out and doesn't connect. Then the clients (e.g. outlook, thunderbird) start taking long to connect and then they timeout. Important: Only IMAP connections timeout! POP3 continues ok. This latency keeps on going until dovecot finally hangs (after about 10 to 15 minutes). The problem is solved when I restart/reload dovecot. I'm not sure as to what's going on! I check the log, but it has been hard to pinpoint an exact event or to detect when the problem begins. Any ideas? BTW: what's the real difference between reload and restart? Thanks a lot! Mario
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thu, 7 Jan 2010, Mario Gomide wrote:> I'm using Dovecot 1.0.7 in RHEL 5.4 64bits as a IMAP/POP3 server.> and stuff. After a while it times out and doesn't connect. Then the clients > (e.g. outlook, thunderbird) start taking long to connect and then they > timeout. Important: Only IMAP connections timeout! POP3 continues ok. This > latency keeps on going until dovecot finally hangs (after about 10 to 15 > minutes). The problem is solved when I restart/reload dovecot.I had similiar problems once. The problem went away after I increased the maximum number of open file descriptors (ulimit -n). Maybe, you should upgrade, v1.0 is pretty old. Regards, - -- Steffen Kaiser -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iQEVAwUBS0XjFb+Vh58GPL/cAQJyVQgApvvpmRWvk+tTepmMrKhMjUxlqBOKZFDF rBmzJ7EvwTCnQziSMlH/ckvg9Z/ccNofBgaosTLXGik9P6jZFzTAcDu6ztNvPYPt 2ldnvDJhUoQCUL+8i594pOy5vs1edm5Tg36d/XHuexL+WiG3a3NuOBu2AgkuVfoa HLk4FNKfKQagquHcpG1z3+R9QJC4rYarg+lU7rNAebF0hEkCyNsZn6DsvRITP4BQ qlauMRS6jQ35o/AYMXuRfJrnektFUFUbT1oyRKwLRF9O3FcSt5fZZ0p6Mv4JLtXZ u8g40iYSF3nfo7J0SFlJjEVbqRjZMtlpNrhPLroa26ztk0GR9YNwtQ==cyU4 -----END PGP SIGNATURE-----
On Thu, 7 Jan 2010 11:08:54 -0200, Mario Gomide <mariogomide at gmail.com> wrote:> Webmail is in localhost and connects locally also with SSL. > > The problem starts when webmail takes long to authenticate and showfolders> and stuff. After a while it times out and doesn't connect. > Any ideas?It may be unrelated to your current problem, but, why in the world are you having a local process connect to another local process via SSL? That's akin to encrypting the traffic between the left and right hemispheres of your brain for fear someone might be listening in to the unencrypted traffic occurring within you skull. Silly isn't it? One thing your configuration will certainly do is suck CPU horsepower, eat up memory unnecessarily, and make things slower than they should/could be. -- Stan
On 8.1.2010, at 15.36, Steffen Kaiser wrote:> If I remember correctly, I made logs of the number of file descriptors of the "dovecot" process; each time the number _almost_ reached the max (say one or two are not allocated yet), I saw the stalls _and_ when I manually logged off users (kill -15 imap-process) the number did not decreased. Well, not much anyway. > Sort of, it looked like a fd leak.If Dovecot runs out of file descriptors, it logs an error. So the most important part: Check if there are any errors in logs. http://wiki.dovecot.org/Logging
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Fri, 8 Jan 2010, Timo Sirainen wrote:>> If I remember correctly, I made logs of the number of file descriptors >> of the "dovecot" process; each time the number _almost_ reached the max >> (say one or two are not allocated yet), I saw the stalls _and_ when I >> manually logged off users (kill -15 imap-process) the number did not >> decreased. Well, not much anyway.>> Sort of, it looked like a fd leak. > > > If Dovecot runs out of file descriptors, it logs an error. So the most important part: Check if there are any errors in logs. http://wiki.dovecot.org/LoggingWell, I know it should, but it does not. Maybe it is something different. I changed my init.d in July 2008, but unfortunately I do not find anything I posted in the mailinglist. There is no sign in the logs, regardless of the auth_debug or mail_debug setting. A telnet to port 143 just hangs without any "connected". However, this is Dovecot v1.0, so I see no reason to dig into it. Regards, - -- Steffen Kaiser -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iQEVAwUBS0dHub+Vh58GPL/cAQJ2Bgf/VBx1tvRqc4mJIC/Bjc3ZhebZEWmm0NSj UaSU3uXum1QCaPZ8BOtZlM4lTFNhnIVvTQj9lzzKeDlu8UB2/OlvghWkqJfk7GpN UJJmlhadEkTqL8iUvRFyz2caClsEN0g5BvCjE/VlBREdeAWHJ/UQvCa7u97m+UZw CG8EMN1eZ7TgPLoLeEmkTcZ3eNL3e9ia2lYFjLYzG0pvsg+VeTZMv+nihN0PmGhY /K5o051kX3CG9fU9TVLhURlW/1HLVV4Cm6yhdb9nCy+KrJZSb+fVCZk5X0PxUUrL LdNZE2DMm7M9t81lUcmMZ2o9AW+dM21q1kg9SGpU3AQumAZ5HY0fLg==CV2a -----END PGP SIGNATURE-----