Considering that a fileserver at home will spend a lot (most) of its life idle, it makes sense to look at its power usage and see what steps can be taken to reduce its operational costs — i.e. power consumption.
The most obvious way to reduce power consumption is to simply turn the machine off when it’s not required. However, some people may wish to leave the machine powered on and put it into low-power mode when it’s not in use.
ACPI suspend state 3 seems to be the low power mode to use. This puts the machine in a low power consumption state, but the machine may be resumed (woken up) using a variety of wake-up events such as hitting a key on the keyboard, moving the mouse, or by sending a magic packet to the network port, known as ‘wake on LAN’, or WOL for short.
First, you need to add a line to the file /etc/power.conf:
Please note that currently this is case sensitive, so ensure the the first ‘S’ of ‘S3’ is upper case! It caught me out.
Then, as root user, you need to enter the following to configure power management:
Then trigger suspend state. If your computer’s power button is configured in the BIOS settings to trigger suspend mode S3 then holding the power button down for a short time like a second should trigger suspend mode.
On my machine, using the hardware mentioned above, a dialog window appeared on the Gnome desktop asking if I wanted to suspend the machine or shut it down. I selected ‘suspend’ and then the screen blanked out, the disks span down, the machine became silent and the LED on the computer’s front panel flashed, indicating suspend mode had been activated. A quick look at the power meter shows around 20W of power consumption instead of around 120W. So far, so good.
However, then I did not manage to wake it up using a keypress, mouse movement or using WOL by sending a magic packet from another machine on the network.
After reboot I inspected /var/adm/messages for any error messages and there were none. The last message said:
Apr 5 20:06:36 solarisbox genunix: [ID 535284 kern.notice] System is being suspended
This is a real pity. Apparently, there was some issue prior to Solaris Nevada build 82, but it was fixed in build 82, and I’m using build 85.
So, time to hunt the newsgroups!
I will update this page with any info or bug id number found.
update December 10th 2008:
Well it seems I may have guessed right earlier — the suspend issue does seem to be related to the graphics card. See the following thread, related to the NVidia GPU-based graphics card I use (Asus EN6200LE):
However, it does seem that a fix has been made and should appear in build 104 (103 is the current build as of December 10th 2008). Once this build is available, this machine should be able to suspend and resume correctly.