Every couple hours we get this error related to temporary session files. The webserver has plenty of disk space and deleting the build up of session files gets our site back up. It's just doesn't make sense.

Warning: Unknown: open(/var/www/davenportlibrary.com/web/www/files/tmp/sess_7t0ge683kib0n41ugegqt42t24, O_RDWR) failed: No space left on device (28) in Unknown on line 0 Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/www/davenportlibrary.com/web/www/files/tmp) in Unknown on line 0