Shadow Copies

Daniel Sinclair, fellow DM instructor, turned me on to this very cool feature yesterday. Under Windows 2003 (and possibly other OSes – I haven’t checked), if you go to the properties for one of your local drives, you will see a tab labeled “Shadow Copies”.  

If you enable the feature, clicking on the Settings button will bring you to a dialog where you can set up a schedule. The basic idea here is that every day/week/month/whatever period you select, the operating system will take a snapshot of your hard drive. Only it’s a smart snapshot – it only records the deltas, making for a much smaller image than if I had simply copied the drive somewhere, and it lets you specify how much space the backups should be allowed to take up.

The way you access the drive is via the network redirector. So you simply open up (say) \\localhost\c$, right-click on any file, and pull up the properties. There’s a “Previous Versions” tab where you can view the state of the file or folder you’re interested in at that point in time.

Obviously, this doesn’t take the place of regular backups, but it sure is a nice safety net, especially when I’m on the road and don’t have access to backup.

One caveat: Dan warned me that there might be a performance penalty associated with enabling this feature. I’m not sure if I’ve noticed anything yet – my hard drive is a bit busy this morning, but I haven’t tracked down what the source of this is yet. It could be something else. At any rate, subjective performance certainly hasn’t suffered that much, if at all.

Thanks Dan!