One thing you could save energy with your fileserver is to use a serial console. Especially if you have such a fancy serial terminal.

To enable OpenSolaris to use a serial Terminal just use the eeprom command.

# eeprom console=ttya

ttya means first serial port, ttyb stands for second serial port.

To be complete, grub also needs to be configured to use the serial console.

Edit /rpool/boot/grub/menu.lst with your favourite sysadmintool (i.e. text editor)

Add the following lines under the default line.

serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal --timeout=10 serial console

unit=0 is for first serial port, unit=1 for second. The second line still allows you to use a standard console through your graphics card. If you don't need that, terminal serial is sufficient.

Have fun!