Resolved Dovecot stop working

[Guillermo Rey]

Good Morning,

I'm using plesk for 10 years. I have several servers but now I have set up a new server and it's driving me crazy.

The server has the CentOS 7 + dovecot + postfix (php 5.5)
Dovecot daemon stops responding randomly in a time between 5 and 10 minutes throwing an IMAP message (empty greeting). The solution is to restart the dovecot daemon and functioning normalizes for another 5 or 10 minutes
It does not seem a high load problem because the server, with 32 GB of RAM, does not seem to be busy.
top - 11:30:54 up 11:12 1 user, load average: 2.12, 2.00, 1.80
Tasks: 266 Total 4 running, 262 sleeping, 0 stopped, 0 zombie
% Cpu (s): 14.0 / 1.5 15 [||||||||||||||| ]
KiB Mem: 32902448 total 426,812 free, 1541204 used, 30934432 buff / cache
KiB Swap: 11286520 Total, 11286520 free, 0 used. Mem avail 30013236

The truth is that I have very angry users and any clues would be appreciated.

 

[IgorG]

Do you have any dovecot error related messages in /var/log/maillog ?
Maybe something like

dovecot: master: Warning: service(imap-login): process_limit (100) reached, client connections are being dropped

?

 

[Guillermo Rey]

Yes

 

[Guillermo Rey]

But..... in my dovecot -n file:
service imap {
process_limit = 2048
service_count = 1
}
service pop3 {
process_limit = 2048
service_count = 1

 

[Guillermo Rey]

Sep 1 09:01:58 srv1000 dovecot: master: Warning: service(imap-login): process_limit (100) reached, client connections are being dropped
Sep 1 09:01:58 srv1000 dovecot: service=imap, [email protected], ip=[79.148.116.199]. Disconnected: Logged out rcvd=120, sent=665
Sep 1 09:01:58 srv1000 plesk_saslauthd[5642]: failed mail authenticatication attempt for user '[email protected]' (password len=5)
Sep 1 09:01:58 srv1000 postfix/smtpd[19294]: warning: 50-77-120-12-static.hfc.comcastbusiness.net[50.77.120.12]: SASL LOGIN authentication failed: authentication failure
Sep 1 09:01:58 srv1000 postfix/smtpd[22607]: connect from 109.red-79-158-139.dynamicip.rima-tde.net[79.158.139.109]
Sep 1 09:01:58 srv1000 dovecot: auth: Debug: client passdb out: CONT#0111#011PDc5NDE2NzQ0MzcyNDU0MTIuMTQ3MjcxMzMxOEBzcnYxMDAwLnNlZ3VyaWRhZGVpbmZvcm1hdGljYS5jb20+
Sep 1 09:01:58 srv1000 postfix/smtpd[19294]: lost connection after AUTH from 50-77-120-12-static.hfc.comcastbusiness.net[50.77.120.12]

 

[IgorG]

Create a file /etc/dovecot/conf.d/99-imap-login.conf with the following content:

service imap-login {
process_limit = 200
process_min_avail = 16
}

You can increase process_limit value according to the server load.

 

[Guillermo Rey]

ok, thank you very much Igor but it´s a plesk error or i made something wrong?

 

[IgorG]

ok, thank you very much Igor but it´s a plesk error or i made something wrong?

I suppose that this additional configuration required due to the specifics of your server and the conditions for server usage.

 

[Guillermo Rey]

But... it i set this
service imap {
process_limit = 2048
service_count = 1
}

it´s not the same process_limit?

 

[Bitpalast]

imap ./. imap-login

 

[Guillermo Rey]

Thanks Peter,

I had understood the difference but there are two things that I think is an error of plesk:
1. login processes are part of the process of imap. If I allow imap processes 2000, the login should have been adjusted to the same value.
2. If not, this parameter must appear in the control panel.