I have an Ubuntu 12.04 server running on Amazon, it's a well seasoned instance that's been running for several years. This is not a shared hosting system, the whole thing is ours. We just started getting error messages relating to disk space, such as:
Warning: session_start(): open(/var/lib/php5/sess_6q18snb4mk50dlige4vb8ch2r3, O_RDWR) failed: No space left on device (28)
SQLSTATE[HY000]: General error: 1 Can't create/write to file '/tmp/#sql_370_0.MYI' (Errcode: 28)
when I check the file system, I get:
df -h Filesystem Size Used Avail Use% Mounted on /dev/xvda1 197G 165G 23G 89% / udev 7.4G 8.0K 7.4G 1% /dev tmpfs 1.5G 176K 1.5G 1% /run none 5.0M 0 5.0M 0% /run/lock none 7.4G 0 7.4G 0% /run/shm
Overall there's plenty of space left. I don't see any partitions in particular trouble. What's the problem?