Servers not appearing while searching in SCOM Report

Question

I am trying to generate performance detail report (CPU and Memory) for several Windows Server 2008 R2 servers but noticed that 4 servers are not appearing & 4 of them are appearing while doing the search. What might be the reason?
I checked under Monitoring -- Microsoft Windows Server -- Operating System Performance. Here I can see all these 8 servers and their respective performance reports. Why it is not showing up while trying to search in report?
Thanks,
Thanks

Answer 1

Heres some generic documentation that I wrote for myself that might help. For processors on server 2008R2 I belive the counter that is grabbing the info is under "Processor Information" and not "Processors" like previous OSs. Also make sure in step
7 to Add group and not object it will be easier if you add the group rather than the object.
1) Launch SCOM and go to the “Reporting” section in the lower left hand side of the console.
2) Expand the “Reporting” folder.
3) Click on the “Microsoft Generic Report Library” folder
4) Open “Performance Detail”
5) This will open the report for configuration, choose the “Change…” button in the upper right hand corner.
6) Select the “New Series” button, this will create a line in the list and represents an object/group you will be reporting on
7) Choose “Add Group…”
8) Search for a server by typing it in the “Group Name” section.
9) Make sure to chose the object with the server and windows icon, the “Class” will also be “Windows Computer”
10) Next, choose the “Browse” button under the rule section (lower right area)
11) The “select rule” window will come up. It will probably be easier to use the “Search by Counter” tab.
12) Under “Performance Object” select the corresponding option that would appear in perfmon. The same goes for “Counter” and then choose “search”. Note – not all performance counters are tracked in SCOM. It will only list what is gathered.
13) Notice the “Management Pack” column in your search, make sure you’re choosing a management pack that applies to your server(s). Select a rule under the counter that applies to the server and choose OK.
14) Select OK in the settings window.
15) Choose your From and To dates and run the report