Mac – Does a TIme Machine backup directory contain full or incremental data

backuprestoretime-machine

I'm having trouble browsing another Time Machine disk. (The regular Time Machine interface doesn't show anything at all.) I can, however, browse the external Time Machine disk's directories. I plan to put the restored data on a second external drive.

Can I restore the entire user folder from the last directory and feel that I've got all the files from the last time machine backup? Or are the contents in that directory an incremental backup?

Best Answer

They're a full backup, in the sense that it contains everything that was in that directory when that snapshot was taken. But it's also sort-of incremental, in that for files (& entire directories) that didn't change between snapshots, it re-uses the same file/directory from the earlier snapshot via hard links.

This means there's only one copy of the unchanged item on the backup disk, but it's in each snapshot that it's valid for. Not just linked from each snapshot, actually in each snapshot. This can be rather hard to visualize, so just treat it as filesystem magic, and don't worry about it too much.

Net result: you can make a Finder copy of the folder from backup, and it'll include everything. Caveat: Time Machine puts some special extended attributes and permissions on the backed-up files, and there's a possibility these might cause trouble. Unfortunately, I don't know the details here...

Also, please don't try to modify the backup (delete items, move/rename them, etc), of you may mess up the backup system's structure.