A look into Time Machine
Tom Yager, one of my favorite tech writers, has posted a great overview of how Time Machine works in Leopard. Imagine my surprise to find out that Apple's backup solution doesn't involve a Flux Capacitor of any kind! It does, however, involve lots of file copying, and clever disk space saving measures. Tom answers some questions about how much work you'll lose if you need to restore from a Time Machine backup (given the nature of how Time Machine saves files that answer varies depending on how far back you need to go). He also sheds some light on what, exactly, Time Machine is doing.If you love your data, you should read this post.
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Reader Comments (Page 1 of 1)
Ryan said 9:33PM on 12-05-2007
pretty much a rehash of what we have all read a 100 times now.
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Chris said 9:47PM on 12-05-2007
Ars had a much better, in-depth look at Time Machine in their Leopard review: http://arstechnica.com/reviews/os/mac-os-x-10-5.ars/14
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Erik Mallinson said 12:39AM on 12-06-2007
Pretty useful, if like myself you hadn't upgraded to Leopard until just a couple days ago. Thanks!
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Think Adrian said 3:25AM on 12-06-2007
AppleInsider too (http://www.appleinsider.com/articles/07/10/12/road_to_mac_os_x_leopard_time_machine.html&page=3)
I actually thought it was a bad article with some flaws. Apart from the first sentance which I found hard to read :)
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sam said 4:51AM on 12-06-2007
What's this? Time machine "works" in Leopard?
This IS news indeed!
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sam said 4:56AM on 12-06-2007
Okay, to explain my last comment.
I have had several batches of time machine backups. At some point or another they all fail. It could be after a few days, it could be after a few weeks - but they all fail.
From there on out time machine will no longer work. The advanced mechanics of time machine are not advanced enough to be fault tolerant and simply skip a file that it gets an error on.
The only solution when this happens is to reformat the drive and start over with time machine.
Some backup program...
If it hasn't happened to you yet, you're lucky. But it will. Just keep backing up. But know this, in the back of your mind, that eventually you'll be wiping those backups clean off your external drive because they have stopped working.
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Nunya said 5:10AM on 12-06-2007
I'm afraid Sam's right. It looks like it's working, and you can get
files back occasionally.... but don't try to switch it off (from
System Preferences), and don't change disks (again from Preferences),
and don't unmount the drive from the desktop, and don't try to Get
Info on the disk. All of these have, at one time or another, frazzled
my drive - fsck_hfs reports invalid extents which cannot be rebuilt -
and a reformat is the only way out. And yes, I did try Disk Warrior.
Galley said 9:01AM on 12-06-2007
Will Time Machine be able to recover a photo I delete today, two years from now?
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James said 2:03PM on 2-07-2008
If your hard drive is big enough, yes. Time Machine begins deleting the oldest backups once the disk is full so it can continue to back up your most recent stuff.
Alex said 9:28AM on 12-06-2007
This really annoys me.
I can't really put my finger on exactly what it is that Apple messes up with, because Spotlight and other things they've done are really well executed, but somehow a lot of things they do, they do flat out do it completely with the wrong approach.
So apparently they don't even do incremental backups, they just simply rename files? Wow, how advanced. Incremental backup systems have been around for years. Subversion, CVS, etc. has been around for years.
After reading that article, I don't even see a use for Time Machine at all. I was going to buy a HD and put it either in my G5 or in my PC, but now I learn you can't use AFP or SMB file shares with TM? What a joke.
It was bad enough that you can't configure Time Machine to back up ONLY certain folders.. Heck, even their simple "Backup" program does that. Nope. You can only tell it what you don't want to back up.
I mean it's really turning out that the only reason to buy Leopard (for most people) is stacks and quick look.
Hey, at least it works. (unlike ahem.. Vista.. which is completely broken in ALL ways)
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niclet said 9:47AM on 12-06-2007
I dunno but Time Machine works fine for me from the beginning. I upgraded directly from Tiger (10.4.10) to Leopard (no clean install). I use an external 2.5" 5400RPM 160Gb for TM with my PowerBook G4 (1.5GHz). I mount/unmount the drive daily and it was cloned once from a 120Gb (with CCC). Time Machine works flawlessly with it and backup/recovery tasks are A1.
Do I have to understand I'm lucky??
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Johnny said 10:57AM on 12-06-2007
I haven't had any problem with Time Machine. I'm not even sure what you guys are talking about. What do you mean, it doesn't do incremental backups, just renames files? Every hour, it finds the files that have changed and backs them up. The files that have not changed, are somehow copied/renamed to appear in the folder with the current backup, therefore giving you the ability to see not only the backed up files but the entire directory structure as it was at that time. We are even using TM in our office on an AFP share and it works fine. It's been working for well over a month now.
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Hemant Torsekar said 12:58PM on 12-06-2007
How about 1.21 Gigawatts ?
Does your hard drive have to be Mac formatted to allow Time Machine's magic to work ?
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