It's quite easy for a disk to have a large number of inodes used even if the disk is not very full.
An inode is allocated to a file so, if you have gazillions of files, all 1 byte each, you'll run out of inodes long before you run out of disk.
It's also possible that deleting files will not reduce the inode count if the files have multiple hard links. As I said, inodes belong to the file, not the directory entry. If a file has two directory entries linked to it, deleting one will not free the inode.
Additionally, you can delete a directory entry but, if a running process still has the file open, the inode won't be freed.
My initial advice would be to delete all the files you can, then reboot the box to ensure no processes are left holding the files open.
By the way, if you're looking for the directories that contain lots of files, this script may help:
#!/bin/bash
# count_em - count files in all subdirectories under current directory.
echo 'echo $(ls -a "$1" | wc -l) $1' >/tmp/count_em_$$
chmod 700 /tmp/count_em_$$
find . -mount -type d -print0 | xargs -0 -n1 /tmp/count_em_$$ | sort -n
rm -f /tmp/count_em_$$find . -xdev -type f | cut -d "/" -f 2 | sort | uniq -c | sort -n
find those little bastards
$ for i in /*; do echo $i; find $i |wc -l; done
This command will list directories and number of files in them. Once you see a directory with unusually high number of files (or command just hangs over calculation for a long time), repeat the command for that directory to see where exactly the small files are.
$ for i in /home/*; do echo $i; find $i |wc -l; done
once you found the suspect – just delete the files
$ sudo rm -rf /home/bad_user/directory_with_lots_of_empty_files
You’re done. Check the results with df -i command again. You should see something like this:
Filesystem Inodes IUsed IFree IUse% Mounted on /dev/xvda 2080768 284431 1796337 14% / tmpfs 92187 3 92184 1% /lib/init/rw varrun 92187 38 92149 1% /var/run varlock 92187 4 92183 1% /var/lock udev 92187 4404 87783 5% /dev tmpfs 92187 1 92186 1% /dev/shm
