According to a new tech note on Apple’s web site, running a Time Machine backup or restore operation while Aperture is running may lead to “inconsistencies” in the Aperture database.
Apple currently recommends that you exclude the Aperture Library from Time Machine backups, and provides instructions for doing so for those unfamiliar with the process.
Be warned: This means that your Aperture Library will not be backed up by Time Machine, so be sure to manually back up your Aperture Library.
A similar situation has been reported if you happen to be running Parallels Desktop for Windows. While unconfirmed, Parallels support also recommends that you exclude the Parallels data directories from Time Machine backups.
Also keep in mind that both iPhoto ’08 and iMovie ’08 use integrated libraries to hold their data.
According to Ars Technica, Time Machine can have issues backing up large files. For one thing, if any portion of a 2GB file changes, Time Machine has to backup the entire 2GB file. This can eat up drive space in a hurry.
This would seem to be an inconsistency on Apple’s part. To quote Ars, “Apple has been encouraging developers to use many small files rather than one big one for years now, mostly to make it easier for Spotlight to index application data. In Tiger, Apple Mail switched to saving individual messages rather than larger, monolithic mailbox files for this reason.”
And yet Aperture, iPhoto, and now iMovie have gone to the “library” approach to storing data.
I guess someone didn’t get the memo.
This issue has been corrected in the OS X 10.5.2 update.