On 13.5.2019 22.56, Root Kev via dovecot wrote:
Hello Group,
We have dovecot deployed as solely a Pop3 service that is used by our applications to pass mail from one application to another internally. We have roughly 4 applications that connect to the Pop3 service every 2 seconds, to check for new messages and pop them for processing if they are present. Depending on the site, we have between 1024-2048MB of memory set for default_vsz_limit. In all systems we see the Out of memory alert several times a day. We previously did not see this at all when running on CentOS6, with less memory.
We have tried increasing the memory to the vsz_limit up to 2gb without success.
We are running on CentOS 7 servers, running dovecot 2.3.6 (7eab80676) (from the dovecot repo).
Can anyone advise any other settings that could be modified in order to correct these out of memory issues?
# dovecot -n # 2.3.6 (7eab80676): /etc/dovecot/dovecot.conf # OS: Linux 3.10.0-957.5.1.el7.x86_64 x86_64 CentOS Linux release 7.6.1810 (Core) # Hostname: ****** #<modified for security> auth_cache_size = 10 M auth_verbose = yes default_vsz_limit = 1 G instance_name = Pop3 Mail Service listen = 10.*.*.* #<modified for security> log_path = /var/log/dovecot.log login_greeting = Pop3 Mail Service login_trusted_networks = 10.*.*.* 10.*.*.* 10.*.*.* 10.*.*.* 10.*.*.* #<modified for security> mail_location = maildir:~/Maildir namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = cache_key=#hidden_use-P_to_show# driver = pam } protocols = pop3 ssl_cert = </etc/pki/dovecot/certs/dovecot.pem ssl_key = # hidden, use -P to show it userdb { driver = passwd } verbose_ssl = yes
May 10 06:44:05 config: Fatal: pool_system_malloc(8192): Out of memory May 10 06:44:05 config: Fatal: master: service(config): child 27887 returned error 83 (Out of memory (service config { vsz_limit=1024 MB }, you may need to increase it) - set CORE_OUTOFMEM=1 environment to get core dump)
Can you try setting
import_environment = $import_environment CORE_OUTOFMEM=1
and see if it causes coredump?
Aki