Windows Home Server Unsupported Feature - Backup Duplication
My wife's laptop died last week and I just successfully restored it from a backup using the Windows Home Server bootable CD. It's so simple it's creepy. I just bought a new harddrive, booted off a CD, and selected a day from over a week's backups and restored. Twenty minutes later I've got her machine back up with a larger hard drive.
As I was poking around my WHS I noticed how much hard drive space was being used on my Storage Tab. I've got four machines backed up, and about 260gigs is used.
Now, "Duplication" (the WHS software-RAID-like feature) isn't turned on by default for backups in Windows Home Server. All my files are duplicated in all my shared, but since a backup is already a duplication of the original, and since you can store multiple days of backups (I have 7 days, so a week's worth of backups over four machines) there's really no reason to duplicate the backup again.
That said, you can go to this totally unsupported and may well go away in the future no warranty express or implied you're on your own don't ask for support from anyone it's your butt not mine Registry key from Regedit:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Home Server\Storage Manager\Folders
From a list of GUIDs, find the one that has the FriendlyName of "Windows Home Server Computer Backup." Under that key there is an "Attributes" sub-key. Create a DWORD value "Reliable" = 1.
(If these instructions are too technical or don't make sense, you might want to reconsider heading down this path, or you can find a nerd to do this. I don't want to make this too easy because if you do this unsupported thing, I'd hate to have your house burst into flames because if it.)
Setting this value does one simple thing, it turns on duplication of the backups database.
- This value isn't referenced or mentioned in the WHS SDK, so it's officially unsupported right now.
- It might go away some day.
- I don't work for the WHS team, so you probably shouldn't listen to me but rather to them.
You might freak out and ask yourself, "why wasn't this turned on by default?" Well, there are some pretty good reasons actually. There can be a significant performance impact. From a team member:
"Whenever you change the contents of a duplicated file, after you close the file, the migrator copies the entire contents of the file to the second disk. The nature of backup is that it frequently makes small changes to large files, meaning that the migrator may end up doing far more work than the backup process does."
That makes sense. If I'm running nightly backups of four machines I could easily see the migrator (the service that makes duplicates) running all night long on my machine. But, I'm also paranoid about losing data so I think this key is for me. It may not be for you, but it's nice to know it's there.