Hi Dovecot community.
We're seeing a ton of imap-login processes running even when using high performance mode (https://doc.dovecot.org/admin_manual/login_processes/#high-performance-mode). According to the docs:
"process_min_avail should be set to be at least the number of CPU cores in the system, so that all of them will be used. Otherwise new processes are created only once an existing one’s connection count reaches client_limit"
We have process_min_avail=4, client_limit=0 and default_client_limit=200000. So we'd expect seeing only 4 imap-login processes serving a ton of connections each. Yet, we see thousands of imap-login processes (more than half of all the imap processes):
$ ps aux | grep imap-login | wc -l 1278 $ ps aux | grep imap | wc -l 2154
We use verbose_proctitle=yes and a there seem to be 2 types of these processes, about half for a single IP and about half we suspect for multiple IPs:
$ ps aux | grep imap-log _apt 1941081 0.0 0.0 10420 8700 ? S 14:57 0:00 dovecot/imap-login [84.115.232.178 TLS proxy] _apt 1941589 0.0 0.0 10532 8648 ? S 14:57 0:00 dovecot/imap-login [119.202.86.160 TLS proxy] _apt 1941789 0.0 0.0 10188 8620 ? S 14:57 0:00 dovecot/imap-login [0 pre-login + 2 TLS proxies] _apt 1942144 0.0 0.0 10716 8748 ? S 14:57 0:00 dovecot/imap-login [0 pre-login + 3 TLS proxies] _apt 1942428 0.0 0.0 10800 8712 ? S 14:57 0:00 dovecot/imap-login [5.41.100.37 TLS proxy] ... $ ps aux | grep imap-log | grep pre-login | wc -l 624 $ ps aux | grep imap-log | grep -v pre-login | wc -l 654
Is having so many imap-login processes normal with our config? Did we misunderstand the docs or is there something wrong here?
default_client_limit = 1048576 default_process_limit = 200000
service imap-login { # client_limit = 0 # default is 0 # process_limit = 0 # default is 0 service_count = 100 process_min_avail = 4 vsz_limit = 2G
inet_listener imap { } inet_listener imaps { haproxy = yes port = 994 } }