The tl;dr for this that tmutil might provide some of what you're looking for, but if you don't trust TimeMachine, you should use a different backup tool.
On Thu, Dec 4, 2014 at 12:25 PM, Michael <keybou...@gmail.com> wrote: > > What I envision: > 1. A tool to list "which files on the backup do not need to be backed up" -- > in other words, the list of files that time machine think are worth backing > up but can be skipped. These can then be sent to a diff-tool to verify that > what is on the backup matches. TimeMachine determines what needs to be backed up by watching FSEvents for directories with changed files. During the backup TM then inspects every file inside the flagged directories. To build your list of files to check, you'd need to do the same thing. > 2. A way to let time machine know that "Hey, this file does not actually > match, and needs to be backed up". "Delete all backups of file X" is one > such, but it is overkill. On the other hand, if the file on the backup is in > error, maybe it should be removed. It is also not quite sufficient, if files > should be backed up but are missing. I don't think there's any method to do this other than modifying the target files so TimeMachine explicitly notices the file. > #1 -- list all files that should be backed up and not need to be re-backed up > -- is needed to avoid worrying about files that do not get backed up. The > idea of "only scan files that are on the backup" will miss files that should > have been but have not because of a bug in time machine itself. In theory, > such a tool can be written today, but I have no idea how. As far as I can > tell, backupd is the only program that has the knowledge to make such a list, > but does not. You could do this with FSEvents. > #2 -- force a backup of specific files -- seems to be impossible at the > moment. Yeah, there's no way to tell TimeMachine to backup a file, aside from modifying the file and starting a backup. > In the past (10.9.5), I had directories where the list of "what was backed > up" did not match the list of "what should have been backed up". So the > concern of "files missing" is not crazy. And the concern of "undetected IO > error in the write" is very real. > > Has anyone looked into this issue? Are there any tools, or any sort of "work > in progress", or anything, to deal with any of this so far? You can use the tmutil command to see what differs in any two snapshots or from a snapshot to the current computer state. There's also fseventer for watching changed files, though I'm not sure if it's still compatible with recent OS versions. All in all though, if you don't feel like you can trust TimeMachine (I wouldn't trust it either if you find it skipping files), you're probably just better off using another tool (rsync, rsnapshot, CarbonCopyCloner, SuperDuper, Crashplan, BackBlaze, etc.). Pick a tool that allows you to more easily verify the backup and manually backup anything that fails verification. -- arno s hautala /-| a...@alum.wpi.edu pgp b2c9d448 _______________________________________________ MacOSX-talk mailing list MacOSX-talk@omnigroup.com http://www.omnigroup.com/mailman/listinfo/macosx-talk
