thanks CFee
-----Original Message----- From: Ben Scott [mailto:mailvor...@gmail.com] Sent: Thursday, July 01, 2010 12:57 PM To: NT System Admin Issues Subject: WinSXS and CBS (was: Where's my disk space) On Thu, Jul 1, 2010 at 11:03 AM, Carol Fee <c...@massbar.org> wrote: > Wow - what the heck is all that ? Short version: A complete copy of every version of every Windows component. Longer version: The WinSxS folder (%SystemRoot%\WinSxS) was originally for "side-by-side installation" of DLLs. Historically, when two different programs tried to install two different, incompatible versions of a DLL with the same name, you were just screwed. This was colloquially termed "DLL hell". SxS helped multiple incompatible DLLs to co-exist on the same system. In Vista, WinSxS was re-purposed/extended to support what Microsoft calls "Component Based Servicing", or "CBS". Windows was divided up into components. Each component exists as an assembly, stored in WinSxS. During base OS install, each and every possible assembly is copied in full to WinSxS. This includes components you de-selected from install in the GUI, and also components for other Editions of Windows. On top of that, when an update is released, every possible version of the updated assemblies (GDR and LDR, for each Service Pack) get stored in WinSxS, along with all the old assemblies. So over time, you're likely to accumulate several copies of most of Windows in there. When a Windows component is actually "installed", the target location is just a link to the component in WinSxS. In theory, this makes servicing easier, because the process is to first copy in the new version of the assembly, then change the links. To "uninstall", you just change the links back. The one ray of sunshine in this is that the links themselves hardly use any space, so the space apparently used by, say, "%SystemRoot%\system32" is actually much less, since it's mostly links to WinSxS. But WinSxS is still typically bigger than any previous entire install of Windows, so it's still a net loss. The Microsoft party line is that WinSxS cannot be moved. It cannot even be usefully managed, except for a very few, select scenarios, such as removing assemblies for a previous Service Pack, or removing incompatible components from Server Core. One should be prepared for WinSxS to consume at least 40 GB of disk space. If you think this is a crazy design, you're not alone, but Microsoft Has Spoken, so get used to it. More information: http://blogs.technet.com/b/askcore/archive/2008/09/17/what-is-the-winsxs-directory-in-windows-2008-and-windows-vista-and-why-is-it-so-large.aspx http://blogs.technet.com/b/joscon/archive/2010/06/12/general-guidance-on-disk-provisioning-for-winsxs-growth.aspx http://blogs.msdn.com/b/ntdebugging/archive/2008/10/21/windows-hotfixes-and-updates-how-do-they-work.aspx http://blogs.msdn.com/b/jonwis/archive/2005/12/28/507863.aspx http://blogs.msdn.com/b/jonwis/archive/2007/01/02/deleting-from-the-winsxs-directory.aspx http://blogs.msdn.com/b/e7/archive/2008/11/19/disk-space.aspx -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
