Fill 'er up and check the oil!
Looks like drives (hda8, 5 and 1) are pushed TO THE LIMIT!!!
Server Load 1.22 (2 cpus)
Memory Used 41.2 %
Swap 0.842 %
Disk hda2 (/) 75 %
Disk hda1 (/boot) 33 %
Disk hda8 (/backup) 98 % <<----------- LOOK
Disk hda7 (/tmp) 3 %
Disk hda6 (/usr) 83 %
Disk hda5 (/var) 95 % <<----------- LOOK
Disk hdc1 (/home) 91 % <<----------- LOOK