du -s /dev = megabytes? found after at least 10G free space disappeared

[George Garvey]

   Suddenly ran out of disk space on a server that had at least 10G free
space. On that system, du -s /dev reports 75616. This doesn't account for
the lack of free space, but it also doesn't make sense. I wonder what else
is going on.
   I can't actually find anything in /dev to account for du's report.
   du /dev reports:
0       /dev/shm
1032    /dev/ataraid
532     /dev/usb
12      /dev/mapper
1028    /dev/raw
0       /dev/pts
480     /dev/snd
24      /dev/video1394
464     /dev/input
12      /dev/logicalco/bci
12      /dev/logicalco/dci1300
32      /dev/logicalco
20      /dev/cpu/3
20      /dev/cpu/10
20      /dev/cpu/11
20      /dev/cpu/8
20      /dev/cpu/9
20      /dev/cpu/6
20      /dev/cpu/15
20      /dev/cpu/14
20      /dev/cpu/4
20      /dev/cpu/13
20      /dev/cpu/12
20      /dev/cpu/2
20      /dev/cpu/0
20      /dev/cpu/5
20      /dev/cpu/7
20      /dev/cpu/1
328     /dev/cpu
16504   /dev/rd
8256    /dev/cciss
16      /dev/compaq
12      /dev/net
76      /dev/scramdisk
8256    /dev/i2o
24      /dev/video
24      /dev/dri
56      /dev/inet
8256    /dev/ida
8       /dev/van01
75616   /dev
   Looking in /dev/rd, all I see are block devices. Looking in /dev, I
don't see anything to account for the difference between the subdirectory
space and the total space.
   It is ext3 on LVM on RAID on IDE on one of the recent Intel
motherboards; FCT2, with no updates.
   Part of our backup system makes backups to hard drives on another
server, across NFS. A du -s of the backup /dev reports 444, closer to
expectations.
   Something has gone very wrong: any suggestions what it might be? There
are other du anomalies, but the one in /dev looked the most egregious. I
thought perhaps finding the source of this symptom would solve the whole
problem.
   Other than doing an fsck after the backup is done shortly, I'll leave
this alone so it can be looked into. I've managed to free up 1G by removing
some unnecessary stuff that is on backup so it can be replaced later.