Buffalo HS-D300GL User Manual page 55

Maintenance Settings - Sleep
Sleep Function: Enable Sleep Function
to allow LinkStation to go into Sleep
Mode. In Sleep Mode, LinkStation's
internal hard drive shuts off until the
Wakeup Time. Disable Sleep Mode if
you want LinkStation to always remain
on. When LinkStation is sleeping, data
cannot be accessed and scheduled
backups will fail.
Schedule Sleep Time: If the Sleep
Function is set to Enable, then enter an
appropriate Disk Sleep Time and Disk
Wake Up Time.
Click Apply to save these settings.