Serverd will raise a power assertion for calenar server.
--- CalendarServer/trunk/contrib/launchd/calendarserver.plist 2012-05-24 00:25:40 UTC (rev 9266)
+++ CalendarServer/trunk/contrib/launchd/calendarserver.plist 2012-05-24 00:36:01 UTC (rev 9267)
@@ -55,5 +55,8 @@
<integer>12000</integer>
</dict>
+ <key>PreventsSleep</key>
+ <true/>
+
</dict>
</plist>