net_connect_unix(imap) failed

[Philipp Ewald]

This was this issue

Thank you!

On 04.04.20 10:48, Alessio Cecchi wrote:
> Hi Philips,
> 
> I have the same error after upgrade from dovecot 2.2 to dovecot 2.3, could be related to "service stats",
> 
> try to grep in the dovecot.log for "reached" and look for an error like:
> 
> dovecot: master: Warning: service(stats): client_limit (1000) reached, client connections are being dropped
> 
> If you find it add to 10-master.conf:
> 
> service stats {
>    client_limit = 10240
>    unix_listener stats-writer {
>      mode = 0660
>      #user = vmail
>      #group = vmail
>    }
> }
> 
> then restart dovecot.
> 
> Let me know if you solve or find others limit reached in the log.
> 
> Ciao
> 
> Il 31/03/20 18:22, Philipp Ewald ha scritto:
>> Hello everyone,
>>
>> we have a huge problem with dovecot and IMAP connections.
>>
>> we got the following errors: 39665 today
>>
>> dovecot: imap-login: Error: master(imap): net_connect_unix(imap) failed: Resource temporarily unavailable - http://wiki2.dovecot.org/SocketUnavailable (client-pid=29066, client-id=1755, rip=IP, created 562 msecs ago, received 0/4 bytes)
>>
>> we thinks this may be a problem with authorization take too long? Authorization is not local and with SQL.
>>
>> i found the following in source code of Dovecot:
>> #define SOCKET_CONNECT_RETRY_MSECS 500
>> #define SOCKET_CONNECT_RETRY_WARNING_INTERVAL_SECS 2
>> [...]
>> i_error("master(%s): %s (client-pid=%u, client-id=%u, rip=%s, created %u msecs ago, received %u/%zu bytes)",
>>
>> This is no process limit problem:
>>
>> ps auxf | grep -c "[d]ovecot/imap$"
>> 688
>>
>> ps auxf | grep -c "[d]ovecot/imap-login$"
>> 100
>>
>>
>> cat /proc/`pidof dovecot`/limits
>> Limit                     Soft Limit           Hard Limit           Units
>> Max cpu time              unlimited unlimited            seconds
>> Max file size             unlimited unlimited            bytes
>> Max data size             unlimited unlimited            bytes
>> Max stack size            8388608 unlimited            bytes
>> Max core file size        0 unlimited            bytes
>> Max resident set          unlimited unlimited            bytes
>> Max processes             64053 64053                processes
>> Max open files            65535 65535                files
>> Max locked memory         65536 65536                bytes
>> Max address space         unlimited unlimited            bytes
>> Max file locks            unlimited unlimited            locks
>> Max pending signals       64053 64053                signals
>> Max msgqueue size         819200 819200               bytes
>> Max nice priority         0                    0
>> Max realtime priority     0                    0
>> Max realtime timeout      unlimited unlimited            us
>>
>> ulimit -n
>> 1024
>>
>>
>> dovecot --version
>> 2.3.4.1 (f79e8e7e4)
>>
>>
>> protocols = imap pop3
>> service imap-login {
>>   process_min_avail = 4
>>   service_count = 0
>> }
>> service imap {
>>   process_limit = 4096
>> }
>> service pop3-login {
>>   process_min_avail = 4
>>   service_count = 0
>> }
>> service pop3 {
>>   process_limit = 4096
>> }
>>
>>
>>
>> Can someone explain why we got this error and how to fix? If you need another information please tell me.
>>
>>
> -- 
> Alessio Cecchi
> Postmaster @http://www.qboxmail.it
> https://www.linkedin.com/in/alessice
> 

-- 
Philipp Ewald
Administrator

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