Background

Recently I have run into a bit of a snag on my home FreeBSD server. I recently upgraded it to the latest stable release, and I have noticed some strange behavior with the /var partition. Originally, I had the system configured such that /var had its own partition with /var/run and /var/log in memory disks (/tmp, too).

After the upgrade, I notice there is a new, fourth memory disk mounting directly to /var that I had not set up manually and is not in my fstab. It is only 28 megs or so in size and is causing problems when trying to update my ports collection. The ramdisk mounts atuomagically at boot and cannot be unmounted while in multi-user mode. If I drop to single user mode, I am able to unmount it without issue, however rebooting causes it to pop right back up.

System specifications have been included at the end of the post.

Question

Is there any way to determine exactly what is mounting a given memory disk (or any filesystem, for that matter) after it has been mounted?

Alternately, does anybody have any ideas what might have caused the new /var ramdisk to pop up?

System Specification

# uname -a

FreeBSD sarge 9.1-PRERELEASE FreeBSD 9.1-PRERELEASE #0: Thu Nov 22 14:02:13 PST 2012     donut@sarge:/usr/obj/usr/src/sys/GENERIC  i386

# df

Filesystem   1K-blocks      Used     Avail Capacity  Mounted on
/dev/da0s1a     515612    410728     63636    87%    /
devfs                1         1         0   100%    /dev
/dev/da0s1d     515612    287616    186748    61%    /var
/dev/da0s1e    6667808   2292824   3841560    37%    /usr
/dev/md0         63004        32     57932     0%    /tmp
/dev/md1          3484         8      3200     0%    /var/run
/dev/md2         31260         8     28752     0%    /var/log
/dev/md3         31260       512     28248     2%    /var       <-- This

# cat /etc/fstab

# Device    Mountpoint  FStype  Options         Dump    Pass#
/dev/da0s1a /       ufs rw,noatime      1   1
/dev/da0s1d /var        ufs rw,noatime      2   2
/dev/da0s1e /usr        ufs rw,noatime      2   2
md      /tmp        mfs rw,-s64M,noatime    0   0
md      /var/run    mfs rw,-s4M,noatime     0   0
md      /var/log    mfs rw,-s32M,noatime    0   0   

Thank you in advance for any assistance.