You are probably familiar with using hdparm for tuning a hard drive, but
it can also save battery life on your laptop, or make life quieter for
you by spinning down drives.hdparm -y /dev/hdb hdparm -Y /dev/hdb hdparm -S 36 /dev/hdb
These commands will: cause the drive to switch to Standby mode, switch to Sleep mode, and finally set the Automatic spindown timeout. This last includes a numeric variable, whose units are blocks of 5 seconds (for example, a value of 12 would equal one minute).