I'm getting the following message all day long:

Oct 5 21:40:05 mail zimbramon[26580]: 26580:crit: Disk warning: mail.snapshotit.com /dev/sdc1 at 99%

Problem is I don't have /sdc1

df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 129G 50G 73G 41% /
varrun 2.0G 40K 2.0G 1% /var/run
varlock 2.0G 4.0K 2.0G 1% /var/lock
udev 2.0G 88K 2.0G 1% /dev
devshm 2.0G 0 2.0G 0% /dev/shm
/dev/sdb1 134G 54G 74G 43% /backup

/dev/sda1 on / type ext3 (rw,errors=remount-ro)
proc on /proc type proc (rw)
/sys on /sys type sysfs (rw)
varrun on /var/run type tmpfs (rw)
varlock on /var/lock type tmpfs (rw)
procbususb on /proc/bus/usb type usbfs (rw)
udev on /dev type tmpfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
devshm on /dev/shm type tmpfs (rw)
/dev/sdb1 on /backup type ext3 (rw)