dovecot/pop3 [blocking on log write] Problem

[evonet]

Hello,
We have 500 e-mail accounts and most of them are POP.I am using centos7 as system. 10 Core processor, 32GB RAM available.Even though we did a fresh install, 6-7 times a day, the mail traffic completely stops and the process monitor shows dovecot/pop3 [blocking on log write].

I'm waiting for your help

 

[evonet]

My file is like this : ( mail_max_userip_connections.conf)


mail_max_userip_connections = 200
remote 127.0.0.1 {
mail_max_userip_connections = 800
}

 

[Zhenyapan]

and where is bottleneck? disks ok? ram enough? cpu?

 

[evonet]

System resources are fine. Available processor and ram available. all of a sudden it says dovecot/pop3 [blocking on log write] in the process monitor. and all mail traffic stops

 

[Zhenyapan]

blocking on log write - maybe disks slow? what "atop" shows at this moment?

 

[evonet]

PID	USER	PR	NI	VIRT	RES	SHR	S	%CPU	%MEM	TIME+	COMMAND
15465	root	20	0	58420	3956	3316	R	6.2	0.0		/usr/bin/top -c -b -n 1
27367	root	20	0	211544	98800	98360	S	6.2	0.3		/usr/lib/systemd/systemd-journald
1	root	20	0	190956	5036	3632	S	0.0	0.0		/usr/lib/systemd/systemd --system --deserialize 15
2	root	20	0	0	0	0	S	0.0	0.0		[kthreadd/3ca427]
3	root	20	0	0	0	0	S	0.0	0.0		[khelper]
100	root	20	0	41528	876	872	S	0.0	0.0		/usr/lib/systemd/systemd-udevd
128	dbus	20	0	58228	3012	2604	S	0.0	0.0		/usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation

• 16:48:27 up 1 day, 4:08, 1 user, load average: 2.06, 2.00, 1.95
• 170 total, 1 running, 168 sleeping, 0 stopped, 1 zombie
• 0.7 us, 1.5 sy, 0.0 ni, 97.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
• 3554432 total, 1850648 free, 3041944 used, 28661840 buff/cache
• 1048576 total, 1043732 free, 4844 used. 30239996 avail Mem

 

[Zhenyapan]

it's a snapshot when dovecot fails? maybe some in system/messages logs?
maybe open_files limit?

 

[evonet]

it's a snapshot when dovecot fails? maybe some in system/messages logs?
maybe open_files limit?

Where can I find the open files limit?

Thank you

 

[Zhenyapan]

check limits for dovecot (last lines) https://easyengine.io/tutorials/linux/increase-open-files-limit/
modify limits https://www.tecmint.com/increase-set-open-file-limits-in-linux/