Check your disk space usage.
I also faced the same problem. I fixed by moving files into another disk.
If you are using Linux OS. You can check the disk usage by using the command:
> df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/xvda1 8256952 7857928 0 100% /
udev 860884 4 860880 1% /dev
tmpfs 347492 188 347304 1% /run
none 5120 0 5120 0% /run/lock
none 868724 0 868724 0% /run/shm
/dev/xvdb 350891748 199364 332868104 1% /mnt
And I moved some files from /dev/xvda1 -> /dev/xvdb partition.
And checked the disk usage.
> df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/xvda1 8256952 2520216 5317308 33% /
udev 860884 4 860880 1% /dev
tmpfs 347492 188 347304 1% /run
none 5120 0 5120 0% /run/lock
none 868724 0 868724 0% /run/shm
/dev/xvdb 350891748 415456 332652012 1% /mnt
Now MySQL server working fine.