esackbauer
So, If I correctly understand this is the way how watchdog checking dovecot functionality . In my case it happening on every 20 seconds. It will be good if there a way to reduce this check frequency.
Its not about the log size, but I think this check is more “aggressive” than it needed 
I am coming from a “physical” email server which was worked fine during the last 15 years , and I never noticed any dovecot crash during this time.
Thank you for your reply
Regards,
HighWay
I have the same problem.
Tried to disable watchdog email notification, but no effect
Apr 10 10:20:33 ac036091fc05 dovecot: imap-login: Disconnected: Aborted login by logging out (no auth attempts in 0 secs): user=<>, rip=172.22.1.13, lip=172.22.1.250, TLS, TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
Apr 10 10:20:33 ac036091fc05 dovecot: imap-login: Disconnected: Aborted login by logging out (no auth attempts in 0 secs): user=<>, rip=172.22.1.13, lip=172.22.1.250
Apr 10 10:20:33 ac036091fc05 dovecot: managesieve-login: Disconnected: Connection closed (no auth attempts in 0 secs): user=<>, rip=172.22.1.13, lip=172.22.1.250