Hello,
running postfix-3.4.7 on Debian 10 I found the following warning in my logs:
postfix/tlsmgr[705]: warning:
lmdb:/var/lib/postfix/smtp_tls_session_cache is unavailable. open
database /var/lib/postfix/smtp_tls_session_cache.lmdb: MDB_MAP_FULL:
Environment mapsize limit reached
on two moderate loaded servers there where thousands of them, each
generated by the same tlsmgr PID
Messages got delivered without other trouble. I guess, simply reusing
TLS sessions did not happen.
The database files /var/lib/postfix/smtp_tls_session_cache.lmdb had
sizes of ~20 and ~32 MB.
I've other instances with smtp_tls_session_cache of 400 MB but there I
use old BDB format and postfix-3.4.6.
I've also other instances where also LMDB is used for
smtp_tls_session_cache and the files are ~40 MB large.
But there, postfix-3.4.5 is installed.
smtp_tls_connection_reuse is explicit set to "yes" and lmdb_map_size
is at it's default ( ~16 MB ) on all of my instances.
For now "rm /var/lib/postfix/smtp_tls_session_cache.lmdb; postfix
reload" made the warning go away.
Wild guess: there where some code changes for tls_fast_shutdown_enable
between 3.4.5 and 3.4.7
(20190615 and 20190723)
Andreas
