Weird /tmp problem

[Gavin Nelmes-Crocker]

I'm suddenly seeing a really strange problem which has bugged me now for 
a couple of days with no resolution

Box Bluequartz (cobalt type OS)

df -h gives below

Filesystem            Size  Used Avail Use% Mounted on
/dev/md1              6.0G  1.4G  4.3G  24% /
/dev/md0               99M   38M   56M  41% /boot
none                 1014M     0 1014M   0% /dev/shm
/dev/md4               62G  8.6G   50G  15% /home
/dev/md2             1012M   34M  927M   4% /tmp
/dev/md3              4.0G  1.7G  2.1G  45% /var

I have Mailscanner-4.57.6-1 installed (upgraded tonight from slightly 
earlier version to see if the problem got resolved.

Problem - When i turn MailScanner on suddenly /tmp starts to fill 
rapidly and i then see an error in the logs

  MailScanner[21007]: ERROR: Unable to create temporary directory

If i do du -h i see below clearly showing there is a problem with /tmp

Filesystem            Size  Used Avail Use% Mounted on
/dev/md1              6.0G  1.4G  4.3G  24% /
/dev/md0               99M   38M   56M  41% /boot
none                 1014M     0 1014M   0% /dev/shm
/dev/md4               62G  8.6G   50G  15% /home
/dev/md2             1012M 1012M     0 100% /tmp
/dev/md3              4.0G  1.7G  2.1G  45% /var

but if i look at a listing with ls -al i see nothing different and more 
importantly nothing taking up massive disk space.

The result is that the users mail gets processed but they get no message 
and no subject the email is blank apart from the Mailscanner headers

As soon as i stop mailscanner and restart sendmail on its own everything 
returns to normal.

Where should i be looking? this was all working until Monday morning 
when it suddenly stopped, as far as i know no reboot or software update 
to cause it - weird

Thanks

Regards

Gavin