Extensive disk use of Windows 2008

The system drive of Windows 2008 consumes a lot of disk space which can be a problem; especially when you use a small c:\ partition (smaller than 40 GB). This article describes how to cleanup files which are not necessary.

-Windows Server 2008 Hibernation 
It looks like Windows 2008 Server enables hibernation by default. This is quite interesting since I’m not sure how many people actually hibernate a server. Nevertheless, it’s something we need to deal with. Particularly for those (like me) who do most of their work in VMs.

 
As you may know, Windows creates a file named hiberfil.sys in the root of the system drive for systems where hibernation is enabled. The hiberfil.sys file is always the same size as physical RAM. In a VM where hibernation is normally replaced with the VM software’s suspend feature, that can be quite a sizeable chunk of wasted space. In a production environment I would normally want to disable hibernation, too.

Trouble is, you can’t disable hibernation anywhere in the GUI. It must be disabled from the command line using the command: 
powercfg.exe /hibernate off

This is further documented in the following MS KB articles:

• http://support.microsoft.com/kb/920730
• http://support.microsoft.com/kb/929658
• How to Disable Hibernation on Windows Vista

Also see my blog post on how to monitor the hibernation settings with OpsMgr.

-WINSXS Folder
After the installation of Windows 2008 server, the WINSXS directory consumed 3 Gb of disk space. After a while and several updates this folder growed to 10 Gb.Windows 2008 stores all language versions for all DLLs it downloads in the normal updating process. Just deleting stuff there is described as mortally dangerous as it contains vital components. 

After installing SP2 (which comes with compcln.exe) you can run this tool and it will clean unnecessary updates.
You can run compcln.exe to cleanup the WINSXS folder.