Time Machine Deep Traversal

[basher]

What's the best way to force Time Machine to perform a deep traversal?

I tried booting into my lion recovery partition, but it did not trigger the traversal.

[baryon]

You could just format your backup and start over, that would definitely force it to backup everything again!

[basher]

Originally Posted by baryon

You could just format your backup and start over, that would definitely force it to backup everything again!

Now that wasn't very helpful.

[Lokheed]

What's a "Deep Traversal?"

[basher]

Originally Posted by Lokheed

What's a "Deep Traversal?"

It essentially tells Time Machine to rescan your drives and rebuild its' database that's used to track changed files.

I've noticed that if I move tens-of-thousands of files around Time Machine gets confused, and TM backups take a longer time than usual.

A deep traversal seems to fix the issue for me.

[Lokheed]

Reading this article, it looks like that extended backup time is a result of TM running a deep traversal.

http://reviews.cnet.com/8301-13727_7-10330125-263.html

Have you checked your logs to see if this indeed the case?

[basher]

Yes, I've checked the logs.

The question here is what is the best way, other than starting TM backups fresh, to force a deep traversal?

[baryon]

Originally Posted by basher

Now that wasn't very helpful.

Why not? It's not like your main hard drive will crash right when you're formatting your backup. You'll only be without a backup for a few minutes.

My Time Machine got screwed up badly recently, and I reformatted it and started the backup from scratch, and now it's running great ever since!

[Lokheed]

Originally Posted by basher

Yes, I've checked the logs.

The question here is what is the best way, other than starting TM backups fresh, to force a deep traversal?

Q: "When time machine starts to back up my machine, it hangs (the clock icon in the top right-hand corner of the screen spins, but the backup disk is not being accessed and currently Time Machine shows no backup in the last five days). Once it has hung, various applications start to behave oddly and generally I am unable to shut them down, even via force quit."


A: There are a variety of reasons why Time Machine could suddenly go slowly. The first and most common is when the backup daemon is doing a "Deep Traversal" of the source drive to ensure its catalog of changed files correctly reflects the status of the source disk. When this happens, Time Machine will stick at "Preparing...," and will note the deep traversal attempt in the system console. This can take a long time, depending on the size of the node being traversed, but usually speeds up once the deep traversal is completed.

Again, from the article, it looks like TM decides when to do a DT (likely when it deems to many files have changed). It looks like that's out of your hands. So I don't see a method to force TM to do (not that I found a ton of documentation on it) this. Moreover, because it does it automatically, I'm not sure why you would want to mess with this? It sounds like if enough files are changed (or other circumstances), TM will perform a DT. I'd say let it do its thing.

I guess I just don't understand your problem here (sorry, maybe I missed something)?