mfs is getting full (/etc/rc.diskless2)

[freebsd]

Hi,

I've setup a firewall with a compact flash instead of a hard-drive.  This is
the output of mount:
/dev/ad0s2a on / (ufs, local, read-only)
mfs:17 on /var (mfs, asynchronous, local)
procfs on /proc (procfs, local)
mfs:36 on /dev (mfs, asynchronous, local)

As you see, I mount the compact flash as read-only and I setup a memory
filesystem for /var

In my rc.conf file:
diskless_mount="/etc/rc.diskless2"
varsize="131072"

Output of: df
Filesystem  1K-blocks   Used Avail Capacity  Mounted on
/dev/ad0s2a    229942 197570 13978    93%    /
mfs:17          63471  56584  1810    97%    /var
procfs              4      4     0   100%    /proc
mfs:36           1503     66  1317     5%    /dev

Output of: df -h
Filesystem    Size   Used  Avail Capacity  Mounted on
/dev/ad0s2a   225M   193M    14M    93%    /
mfs:17         62M    55M   1.8M    97%    /var
procfs        4.0K   4.0K     0B   100%    /proc
mfs:36        1.5M    66K   1.3M     5%    /dev

Output of: du -h -d 1 /var
364K    /var/db
1.0K    /var/account
3.0K    /var/at
1.0K    /var/backups
1.0K    /var/crash
2.0K    /var/cron
1.0K    /var/empty
5.0K    /var/games
1.0K    /var/heimdal
3.2M    /var/log
 31K    /var/mail
2.0K    /var/msgs
1.0K    /var/preserve
 47K    /var/run
1.0K    /var/rwho
 16K    /var/spool
3.0K    /var/tmp
1.0K    /var/yp
1.6M    /var/mrtg
2.0K    /var/ucd-snmp
5.3M    /var

Output of: du -d 1 /var
364     /var/db
1       /var/account
3       /var/at
1       /var/backups
1       /var/crash
2       /var/cron
1       /var/empty
5       /var/games
1       /var/heimdal
3299    /var/log
31      /var/mail
2       /var/msgs
1       /var/preserve
47      /var/run
1       /var/rwho
16      /var/spool
3       /var/tmp
1       /var/yp
1670    /var/mrtg
2       /var/ucd-snmp
5456    /var

It seems to have a big difference between the output of df and du.
My problem is, my /var partition is getting filled very quickly and I don't
know why ?  I don't know what to clean.  I've already deleted some log, but
I saved only 2% of free space or 1000 block.

I don't know what is taking all this space ?  Any ideas ?

Vincent Goupil