How to configure Xserve to go into sleep mode when Energy Saver setting don't work? This question relates to an earlier question, but as it seems a unique and contained problem I thought it merited its own.

To review I have a home office network comprised of:


Time Capsule
27" iMac with dual cores running Mac OS X 10.6.8 and
2 Xserves each with 2 quad cores running Max OS X Server 10.6.8
All networking by Ethernet


I access the Xserves through Finder -> Share Screen.  This works fine.

I use the Xserves to run parallel calculations for about 5 minutes a day. As the machines run hot and loud as well as use a considerable amount of power, I want them to "Sleep" when I don't need to actually run the calculations, even better if they fall asleep on their own!

So, I went into the Xserver's System Preferences, opened Energy Saver, and configured the settings as you can see below:

 

The Xserves should fall asleep after about 5 minutes of inactivity. They don't.  

Not even when I have the "Share Screen" window closed.

Note, I need "Wake for Ethernet network access" checked because I want to use "Wake On LAN" capability to wake the Xserves from a remote computer.

I can put the Xserves to sleep manually from the "Share Screen" window, but having to do that just seems silly.

Any ideas of what I need to do get them to fall asleep?
Well, XServes are servers after all, designed to provide user services 24/7/365. I bet that there are some services (web serving, mail, iChat, etc,) turned on by default that you must first turn off before the Xserve can sleep. If you didn't setup these Xserves yourself, (or even if you did,) this Snow Leopard Server Getting Started manual may help you to find out how to look for these services in the Server Admin app to shut them down. This Snow Leopard Server Installation &amp; Setup Worksheet may also provide you with more insight.

Through Network Utility on the Xserve itself, or on the remote machine using the Xserver IP address, you could use the Port Scan tab to find out which services are being advertized, and thus which services are running. Here's a handy chart of the ports Snow Leopard Server uses.