I had occasion to use the services of Leopard’s Time Machine backup over the weekend and decided to post some quick notes. None of this is bad, it just might be good to know what to expect going in.
After corrupting my local iTunes library (through a stupid mistake) while trying to get it to work off of a Windows Home Server I decided to go the restore route rather than try to fix the problem and miss something. I knew it would work and I could go do other things while it happened. My iTunes folder is about 139GB and it’s on a 433GB partition. All the iTunes files were still there so there was less than 139GB free on disk when I started the restore.
I went into Time Machine and started a restore from the last backup made before I started working on moving the library. It displayed a message saying there wasn’t enough space to do the restore without overwriting existing files and asked if I wanted to continue. I let it overwrite the existing files. Most files were unchanged since they were backed up but Time Machine still overwrote all the files (which I consider a good thing).
The downside to this occurred during the next Time Machine backup, although it wasn’t serious.
Time Machine wanted to backup the entire iTunes folder again. First, there wasn’t enough free space on the Time Machine drive so it told me that it needed to delete old backups and the oldest backup was now Nov 3rd. Whenever I went in to check the status during the backup it always showed XXGB out of XXGB backed up where the numbers always matched. Each time I checked the numbers were higher but equal. Eventually I received a timeout error with the message that the backup failed. When the next scheduled Time Machine backup rolled around it completed the backup. Based upon how little the free space actually went down, and how fast the backup ran, it appears Time Machine used pointers to existing files when they were already on the Time Machine drive.
After moving the iTunes library I renamed the old iTunes folder on my Mac rather than delete it. The next time Time Machine ran a backup it backed up this entire 139GB in directory structure again. Based upon the backup time and drop in free space it actually backed up the files again even though the files themselves were already there on the drive in another folder tree.
This was my first real occasion to use Time Machine and it was nice to see it work as expected. The iTunes library worked find after the restore.