Designed to Fail: Apple Time Machine and MacOS X Server (With Some New Thoughts)


In my original posting, I gripe that Time Capsule makes a royal mess of things for a MacOS X Server box. And it does, still, unless you do some system file editing.

But I’ve had a few thoughts since then, especially since I just went through this whole scenario again last night. This time, I was better prepared, though, as the system file editing I describe in that article saved my bacon.

Or my users’ IMAP data. Bacon, IMAP data… if only IMAP data tasted as good… mmm… bacon…

Sorry. Back to reality.

Apple has chosen to keep several /var directories out of the Time Machine backups because they change rapidly, there’s a lot of data, and it would fill up the backup disk PDQ. Wisely, they also include some preferences in the exclusions file to take care of this little problem, namely the keys “PathsExcluded”, “ContentsExcluded”, and “FileContentsExcluded”.

Entire directories can be excluded with the first, the contents of directories can be excluded with the second (i.e., it preserves the top directory structure, but doesn’t backup any files or subdirectories), and the third backs up all of the subdirectory structures, but still no files. Googing these three terms yields nothing, so I assume I have a correct understanding of what they do.

If I do understand these correctly, then there’s a fourth kind that needs to be created, namely something which means “backup only the file permissions, names, ACLs, etc., but don’t backup the data in the files.” This key would allow the /var/log directory backup to maintain zero-length backup files (hence, they never change) but allow not-so-smart software which doesn’t/can’t create its own logfiles when missing (Apache, I’m lookin’ at you) to use them when restored from backup.

Maybe one of these keys means exactly that, but I’ll be darned if I know which one, and, like I said, there doesn’t seem to be any documentation on it.

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