Have you ever received the message “No space left on device” but your disk is not full? This could be an issue with the available inodes on the partition in question. To check your current inode usage just type:
df -hi
You want to specifically check the column named IUse% for the partition that you are experiencing the issue. If it is 100% then this partition has used up all available inodes. Essentially, somewhere on the partition in question there are a lot of small files that are using up all the partitions inodes (but not taking up physical space). To track down the directory that all these files are being stored in just use the command:
find [path to partition] -type d -exec sh -c 'ls "$1" | wc -l' {} {} \; -print | sed '$!N;s/\n/ /' | sort -n