db directory filling up - normal or config error?

[Carl Brewer]

I asked this a few months ago, but now it's getting urgent.  I have a 
NetBSD 5.x server, running Cyrus imapd 2.4.17 from pkgsrc, /var/imap/db 
is getting very full :

bash-4.3# du -sh db
7.0G    db

(this is on a reasonably small server)

and it grows every day, it's full of these :

-rw-------   1 cyrus  mail  10485760 Feb  1 03:47 log.0000000953
-rw-------   1 cyrus  mail  10485760 Feb  2 03:48 log.0000000954
-rw-------   1 cyrus  mail  10485760 Feb  3 03:47 log.0000000955
-rw-------   1 cyrus  mail  10485760 Feb  4 03:46 log.0000000956
-rw-------   1 cyrus  mail  10485760 Feb  5 03:47 log.0000000957
-rw-------   1 cyrus  mail  10485760 Feb  6 03:46 log.0000000958
-rw-------   1 cyrus  mail  10485760 Feb  7 03:46 log.0000000959
-rw-------   1 cyrus  mail  10485760 Feb  8 03:46 log.0000000960
-rw-------   1 cyrus  mail  10485760 Feb  9 03:47 log.0000000961
-rw-------   1 cyrus  mail  10485760 Feb 10 03:48 log.0000000962


a new one every day.  This is not sustainable on this little server.

I'm not sure if cyrus itself is supposed to clean these up?

My cyrus.conf is :
# standard standalone server implementation

START {
   # do not delete this entry!
   recover       cmd="ctl_cyrusdb -r"

   # this is only necessary if using idled for IMAP IDLE
#  idled                cmd="idled"
}

# UNIX sockets start with a slash and are put into /var/imap/socket
SERVICES {
   # add or remove based on preferences
   imap          cmd="imapd" listen="localhost:imap" prefork=0
   imaps         cmd="imapd -s" listen="imaps" prefork=0
   pop3          cmd="pop3d" listen="pop3" prefork=0
   pop3s         cmd="pop3d -s" listen="pop3s" prefork=0
   #sieve                cmd="timsieved" listen="sieve" prefork=0

   # these are only necessary if receiving/exporting usenet via NNTP
#  nntp         cmd="nntpd" listen="nntp" prefork=0
#  nntps                cmd="nntpd -s" listen="nntps" prefork=0

   # at least one LMTP is required for delivery
#  lmtp         cmd="lmtpd" listen="lmtp" prefork=0
   lmtpunix      cmd="lmtpd" listen="/var/imap/socket/lmtp" prefork=0

   # this is only necessary if using notifications
#  notify       cmd="notifyd" listen="/var/imap/socket/notify" 
proto="udp" prefo
rk=1
     # Carl, 20140806
    smmapd       cmd="smmapd" listen="/var/imap/socket/smmapd" prefork=1
}

EVENTS {
   # this is required
   checkpoint    cmd="ctl_cyrusdb -c" period=30

   # this is only necessary if using duplicate delivery suppression,
   # Sieve or NNTP
   delprune      cmd="cyr_expire -E 3" at=0400

   # this is only necessary if caching TLS sessions
   tlsprune      cmd="tls_prune" at=0400
}



Have I done something wrong, config-wise?  Or is there a way to safely 
purge these db log files?

Thank you!

Carl