While investigating my earlier Sendmail confusion I noticed these files:
# ll /var/lib/imap/db/ total 15952 -rw------- 1 cyrus mail 16384 Jan 22 04:02 __db.001 -rw------- 1 cyrus mail 663552 Jan 22 04:02 __db.002 -rw------- 1 cyrus mail 98304 Jan 22 04:02 __db.003 -rw------- 1 cyrus mail 22568960 Jan 22 04:02 __db.004 -rw------- 1 cyrus mail 32768 Jan 22 04:02 __db.005 -rw------- 1 cyrus mail 64 Jan 22 04:02 log.0000000001
The date/time stamps suggest that these files were create by a cron job the day after I installed CentOS v4.2 and have not been modified since.
I haven't done any explicit Cyrus configuration, and actually I don't have a clear idea of what mail-related functionality Cyrus actually provides. If it is in use at all on my system it is done as some aspect of the default CentOS4 installation. Those __db files are not owned by any RPM package, although the /var/lib/imap/db/ is owned by the cyrus-imapd package.
Do I really need a 22MB empty database file on my system?