[Dovecot] imap-login process_limit reached
I've been having some problems with IMAP user connections to the Dovecot (v2.0.8) server. The following message is being logged.
Jan 16 10:51:36 postal dovecot: master: Warning:
service(imap-login): process_limit reached, client connections are
being droppedThe server is running Red Hat Enterprise Linux release 4 (update 6). Dovecot is v2.0.8.
We have only 29 user accounts in /etc/dovecot/users. There were 196 "dovecot/imap" processes and 6 other dovecot processes, for a total of 202 "dovecot" processes, listed in the 'ps aux' output when problems were being experienced.
Stopping and restarting the Dovecot system fixes the problem -- for a while.
The 'doveconf -n' output is attached. I have not set any "process_limit" values, and I don't think I'm getting anywhere close to the 1024 default, so I'm pretty confused as to what might be wrong.
Any suggestions on what to do next are appreciated.
Thanks,
- Don
# 2.0.8: /etc/dovecot/dovecot.conf # OS: Linux 2.6.9-67.0.1.ELsmp i686 Red Hat Enterprise Linux WS release 4 (Nahant Update 6) ext3 auth_username_format = %Lu auth_verbose = yes auth_verbose_passwords = sha1 login_log_format_elements = user=<%u> service=%Us method=%m rip=%r lip=%l mpid=%e %c login_trusted_networks = xx.xx.xx.0/24 mail_location = maildir:/Virtual_Users/%u/Mail passdb { args = scheme=CRYPT username_format=%u /etc/dovecot/users driver = passwd-file } passdb { driver = pam } ssl_ca =
First of all, feature request:
doveconf -d show the default value of all settings
On 01/16/12 17:41, Don Buchholz wrote:
The 'doveconf -n' output is attached. I have not set any "process_limit" values, and I don't think I'm getting anywhere close to the 1024 default, so I'm pretty confused as to what might be wrong.
Any suggestions on what to do next are appreciated.
What makes you think 1024 is the default? We had to increase it. It shows up in doveconf -n output, so I don't think that's the default.
# doveconf -n | grep limit default_process_limit = 1024
On Tuesday, January 17, 2012 at 14:23:47 UTC, michael@orlitzky.com confabulated:
First of all, feature request:
doveconf -d show the default value of all settings
You mean like doveconf(1) ?
OPTIONS -a Show all settings with their currently configured values.
-- If at first you don't succeed... ...so much for skydiving.
On 01/17/12 09:31, Duane Hill wrote:
On Tuesday, January 17, 2012 at 14:23:47 UTC, michael@orlitzky.com confabulated:
First of all, feature request:
doveconf -d show the default value of all settings
You mean like doveconf(1) ?
OPTIONS -a Show all settings with their currently configured values.
Using -a shows you all settings, as they're running in your installation. That's the defaults, except where they're overwritten by your config.
I was asking for the defaults regardless of what's in my config file, so that I don't have to deduce them from the combined doveconf output & my config file.
On 01/17/12 09:58, Michael Orlitzky wrote:
Using -a shows you all settings, as they're running in your installation. That's the defaults, except where they're overwritten by your config.
I was asking for the defaults regardless of what's in my config file, so that I don't have to deduce them from the combined doveconf output & my config file.
In other words, I don't want to have to do this:
mail2 ~ # touch empty-config.conf mail2 ~ # doveconf -a -c empty-config.conf | grep limit | head doveconf: Error: ssl enabled, but ssl_cert not set doveconf: Error: ssl enabled, but ssl_cert not set doveconf: Fatal: Error in configuration file empty-config.conf: ssl enabled, but ssl_cert not set default_client_limit = 1000 default_process_limit = 100 default_vsz_limit = 256 M recipient_delimiter = + client_limit = 0 process_limit = 1 vsz_limit = 18446744073709551615 B client_limit = 1 process_limit = 0 vsz_limit = 18446744073709551615 B
to find out that the default process limit isn't 1000.
On 2012-01-17 9:58 AM, Michael Orlitzky michael@orlitzky.com wrote:
Using -a shows you all settings, as they're running in your installation. That's the defaults, except where they're overwritten by your config.
I was asking for the defaults regardless of what's in my config file, so that I don't have to deduce them from the combined doveconf output& my config file.
Yeah, I had suggested this to Timo a long time ago when I suggested doveconf -n (the way postfix does it), but I don't think he ever did the -d option... maybe it got lost in the huffle...
--
Best regards,
Charles
Michael Orlitzky wrote:
First of all, feature request:
doveconf -d show the default value of all settings
On 01/16/12 17:41, Don Buchholz wrote:
The 'doveconf -n' output is attached. I have not set any "process_limit" values, and I don't think I'm getting anywhere close to the 1024 default, so I'm pretty confused as to what might be wrong.
Any suggestions on what to do next are appreciated.
What makes you think 1024 is the default? We had to increase it. It shows up in doveconf -n output, so I don't think that's the default.
# doveconf -n | grep limit default_process_limit = 1024
What makes me think 1024 is the default? The documentation: --> http://wiki2.dovecot.org/Services?highlight=%28process_limit%29#imap.2C_pop3...
On 01/17/12 13:15, Don Buchholz wrote:
What makes me think 1024 is the default? The documentation: --> http://wiki2.dovecot.org/Services?highlight=%28process_limit%29#imap.2C_pop3...
That's only for those three services (imap, pop3, managesieve), not for imap-login unfortunately. Check here for more info,
http://wiki2.dovecot.org/LoginProcess
but the good part is,
Since one login process can handle only one connection, the service's process_limit setting limits the number of users that can be logging in at the same time (defaults to default_process_limit=100).
Michael Orlitzky wrote:
On 01/17/12 13:15, Don Buchholz wrote:
What makes me think 1024 is the default? The documentation: --> http://wiki2.dovecot.org/Services?highlight=%28process_limit%29#imap.2C_pop3...
That's only for those three services (imap, pop3, managesieve), not for imap-login unfortunately. Check here for more info,
http://wiki2.dovecot.org/LoginProcess
but the good part is,
Since one login process can handle only one connection, the service's process_limit setting limits the number of users that can be logging in at the same time (defaults to default_process_limit=100).
Doh! Thanks, Michael. I wasn't looking at the original error message closely enough. I scanned too quickly and saw "service(imap)" and not "service(imap-login)". Now the failure when there are only ~200 (total) dovecot processes makes sense (because about half of the processes here are dovecot/imap-login).
I've added the following to our configuration:
service imap-login {
process_limit = 500
process_min_avail = 2
}Thanks for your help ... and patience.
- Don
On 01/17/12 14:48, Don Buchholz wrote:
Doh! Thanks, Michael. I wasn't looking at the original error message closely enough. I scanned too quickly and saw "service(imap)" and not "service(imap-login)". Now the failure when there are only ~200 (total) dovecot processes makes sense (because about half of the processes here are dovecot/imap-login).
...
Thanks for your help ... and patience.
No problem, I went through the exact same process when we hit the limit.
Don Buchholz wrote:
Michael Orlitzky wrote:
First of all, feature request:
doveconf -d show the default value of all settings
On 01/16/12 17:41, Don Buchholz wrote:
The 'doveconf -n' output is attached. I have not set any "process_limit" values, and I don't think I'm getting anywhere close to the 1024 default, so I'm pretty confused as to what might be wrong.
Any suggestions on what to do next are appreciated.
What makes you think 1024 is the default? We had to increase it. It shows up in doveconf -n output, so I don't think that's the default.
# doveconf -n | grep limit default_process_limit = 1024
What makes me think 1024 is the default? The documentation: --> http://wiki2.dovecot.org/Services?highlight=%28process_limit%29#imap.2C_pop3...
But, Michael's right, documentation can be wrong. So, I dumped the entire configuration. Here are the values found on the running system. Both imap and pop3 services have "process_limit = 1024".
| [root@postal ~]# doveconf -a
| # 2.0.8: /etc/dovecot/dovecot.conf
| # OS: Linux 2.6.9-67.0.1.ELsmp i686 Red Hat Enterprise Linux WS release 4 (Nahant Update 6) ext3 | ... | default_process_limit = 100 | ... | service anvil { | ... | process_limit = 1 | ... | } | service auth-worker { | ... | process_limit = 0 | ... | } | service auth { | ... | process_limit = 1 | ... | } | service config { | ... | process_limit = 0 | ... | } | service dict { | ... | process_limit = 0 | ... | } | service director { | ... | process_limit = 1 | ... | } | service dns_client { | ... | process_limit = 0 | ... | } | service doveadm { | ... | process_limit = 0 | ... | } | service imap-login { | ... | process_limit = 0 | ... | } | service imap { | ... | process_limit = 1024 | ... | } | service lmtp { | ... | process_limit = 0 | ... | } | service log { | ... | process_limit = 1 | ... | } | service pop3-login { | ... | process_limit = 0 | ... | } | service pop3 { | ... | process_limit = 1024 | ... | } | service ssl-params { | ... | process_limit = 0 | ... | }
On 01/17/12 14:02, Don Buchholz wrote:
But, Michael's right, documentation can be wrong. So, I dumped the entire configuration. Here are the values found on the running system. Both imap and pop3 services have "process_limit = 1024".
You probably just posted this while my last message was in-flight, but just in case, 'imap' and 'imap-login' are different, and have different process limits.
As the title of the thread suggests, you're out of imap-login processes, not imap ones.
Michael Orlitzky wrote:
On 01/17/12 14:02, Don Buchholz wrote:
But, Michael's right, documentation can be wrong. So, I dumped the entire configuration. Here are the values found on the running system. Both imap and pop3 services have "process_limit = 1024".
You probably just posted this while my last message was in-flight, but just in case, 'imap' and 'imap-login' are different, and have different process limits.
As the title of the thread suggests, you're out of imap-login processes, not imap ones.
Yup! ... see reply on other branch in this thread. Thanks again!
- Don
On 17.1.2012, at 16.23, Michael Orlitzky wrote:
First of all, feature request:
doveconf -d show the default value of all settings
On 2012-01-28 3:24 PM, Timo Sirainen tss@iki.fi wrote:
On 17.1.2012, at 16.23, Michael Orlitzky wrote:
First of all, feature request:
doveconf -d show the default value of all settings
Awesome, thanks Timo!
This makes it much easier to make sure that you aren't specifying anything which would be the same as the default, which minimizes doveconf -n 'noise'...
--
Best regards,
Charles
On Mon, 2012-01-16 at 14:41 -0800, Don Buchholz wrote:
I've been having some problems with IMAP user connections to the Dovecot (v2.0.8) server. The following message is being logged.
Jan 16 10:51:36 postal dovecot: master: Warning: service(imap-login): process_limit reached, client connections are being dropped
Maybe this will help some in future: http://hg.dovecot.org/dovecot-2.1/rev/a4e61c99c7eb
The new error message is:
service(imap-login): process_limit (100) reached, client connections are being dropped
Timo Sirainen wrote:
On Mon, 2012-01-16 at 14:41 -0800, Don Buchholz wrote:
I've been having some problems with IMAP user connections to the Dovecot (v2.0.8) server. The following message is being logged.
Jan 16 10:51:36 postal dovecot: master: Warning: service(imap-login): process_limit reached, client connections are being droppedMaybe this will help some in future: http://hg.dovecot.org/dovecot-2.1/rev/a4e61c99c7eb
The new error message is:
service(imap-login): process_limit (100) reached, client connections are being dropped
Great idea! Thanks, Timo.
- Don
participants (5)
-
Charles Marcus
-
Don Buchholz
-
Duane Hill
-
Michael Orlitzky
-
Timo Sirainen