Проверьте, вращается ли жесткий диск или во сне

Попробуйте hdparm.

-C     Check  the current IDE power mode status, which will always be one of unknown 
       (drive does not support this command), active/idle (normal operation), standby
       (low  power  mode,  drive  has spun  down), or sleeping (lowest power mode, 
       drive is completely shut down).  The -S, -y, -Y, and -Z options can be used to
       manipulate the IDE power modes.

Что-то как

sudo hdparm -C /dev/sdb