Since the Lenny version of +Debian Edu / Skolelinux, a +feature to save power have been included. It is as simple as it is +practical: Shut down unused clients at night, and turn them on again +in the morning. This is done using the +shutdown-at-night Debian package.
+ +To enable this feature on a client, the machine need to be added to +the netgroup shutdown-at-night-hosts. For Debian Edu, This is done in +LDAP, and once this is in place, the machine in question will check +every hour from 16:00 until 06:00 to see if the machine is unused, and +shut it down if it is. If the hardware in question is supported by +the +nvram-wakeup +package, the BIOS is told to turn the machine back on around 07:00 +- +10 minutes. If this isn't working, one can configure wake-on-lan to +try to turn on the client. The wake-on-lan option is only documented +and not enabled by default in Debian Edu.
+ +It is important to not turn all machines on at once, as this can +blow a fuse if several computers are connected to the same fuse like +the common setup for a classroom. The nvram-wakeup method only work +for machines with a functioning hardware/BIOS clock. I've seen old +machines where the BIOS battery were dead and the hardware clock were +starting from 0 (or was it 1990?) every boot. If you have one of +those, you have to turn on the computer manually.
+ +The shutdown-at-night package is completely self contained, and can +also be used outside the Debian Edu environment. For those without a +central LDAP server with netgroups, one can instead touch the file +/etc/shutdown-at-night/shutdown-at-night to enable it. +Perhaps you too can use it to save some power?
+ +