MacMost Now 512: Time Machine Versus Cloning

Learn how Time Machine is different than most backup solutions that simply clone and update the data on a drive. Time Machine saves multiple copies of your files and allows you to access each version as long as it has space.

Video Transcript
Hi, this is Gary with MacMost Now. On today's episode, let's look at how Time Machine works and compare it to Cloning. Time Machine is the backup software that's part of OS X. You should be using it to back up all the files on your hard drive. An alternative that some people use are clones; and you can use cloning software to create a complete clone of your hard drive. Let's look at how Time Machine works and compare it to cloning.
So here are some files that may be on your computer. You can see I got a bunch of things here at the bottom of the screen: some text files, images, music, all sorts of things. Now on your drive, you have one copy of each one. The Time Machine, when you make your first backup, we'll call that NOW, it copies one of these files to the drive. So, you've got a backup of your entire drive. Now, the next time it goes to backup, an hour later, it is gonna check every one of those files and see which one has been updated. Now in this case, as an example, we've got this one document here has been updated, and a image right here has been updated. So, it has the current update right there, and it has the one from an hour ago, the original update. So, notice that it doesn't bother to make new copies of the files that have remained the same, but it does make new copies of the ones that have changed. So, not only do you have a copy of everything on there, but you have a copy, say of this document right here, the current one, and you have the old one as well.
Now, if we look what happens over a longer period of time, we can see here that Time Machine has a few hourly backups from today, but that it also has ones that are from yesterday, from two days ago and all the way back to the original one, which may be several days old. And you can see that file.txt has changed just recently and it has that in copy and the old original copy. changing all the time, so it has a copy with every backup it's got, and various other stage for these other things. Some of these files, like this image here, and this zip file here have never changed since the original and it's never bothered to make a backup.
Now, one of the important things to know with Time Machine is of course, it's eventually gonna run out of space; I mean look at all of these copies of paper.doc. So, if you move forward in time here, you can see Time Machine cleans itself up and says I don't need all the really old files. I just wanna save as many recent versions of each one as I can. So it has many recent versions of paper.doc, but it stopped, uh, keeping them after two days old. File.txt, it threw away the original and it has the newer one, and the same with the rest of these. So, you can't rely on Time Machine to actually keep an archive of what you really got going on. Basically, it's going to have one copy, your most recent copy of every file on your drive; and it's going to have, maybe several versions going back in time depending on how often you update and how big the file is, how much space is on your Time Machine drive.
Now clone is a very different thing; you have to get a piece of software. One is called SuperDuper!, and another one that you may find is called Carbon Copy Cloner, and you can get trial versions of both of these, and they'll create a complete clone of your hard drive. Let's see what that looks like.
So with a clone you can have exactly one copy of every file on the clone. Basically, right after you finish making a clone, it should look exactly like your hard drive. So if you look at in a time format, you can see that it has one copy of every file, now some of them may be very recent; like this one is a new one from the current clone and this one is a new one from the current clone, but other ones are older. The idea is that it still does it incrementally. You do a clone and it creates one copy of every file. Then you do an update on that clone and it sees that these two files need to be updated. It deletes the old one and replaces it with a new one, so you have an up-to-date clone of your drive. If you look over time, you may find that some of those files are very old and some of them are new. It's still going to be the most recent copy of every file, so it's an exact copy of your hard drive. It's just that it's important to know that there are no older copies, say of paper.doc her, only the most recent one.
So here are some of the advantages of cloning. First is that it uses less drive space. It only takes one terabyte to back up a terabyte drive cause there is one copy of every file. Ah, clones are often bootable, meaning since it is an exact copy, if you've done it correctly and made a bootable clone, then you can actually replace your failed hard drive with the cloned drive and get right back into work. Now of course, that doesn't work very well if you've actually updated some of your files since the last time you've made the clone, which is very likely cause how often can you make a clone? Maybe once a day. Another is more control. With clones you can say I wanna back up this and not that, I want to back up at certain times, so we have a ton of control; what gets back up and when.
Now Time Machine, one of the big advantages is it's automatic. You start Time Machine working and it's going to make small incremental back ups every hour and you don't have to worry about it. It's gonna keep doing it, and if you do have a hard drive failure or something goes wrong, chances are you have a very recent copy of all your files because Time Machine's been working in the background to make copies. Now there is, of course, you have this great history; so you're not only protected against a complete hard drive failure, but say, if you screw up, accidently delete a file or modify a file and you realize, boy I really wish I could go back to how this file was yesterday or three hours ago, you can do that with Time Machine.
Another huge advantage of Time Machine is it works, not only with a finder for files, but it works in other programs like iPhoto and Mail. You can actually run time machine while say in iPhoto and look at previous versions of photos or mail messages; even works with address books to look at previous versions of contacts. And of course, a big advantage of Time Machine is it's into OS X; you can start using it as soon as you get an external hard drive or a time capsule.
So what do I recommend? For most Mac users I recommend using Time Machine. Get an external hard drive and USB drive that's at least twice the size of your internal and simply turn Time Machine on, use that entire drive as your Time Machine drive and let Time Machine handle your back ups.
Now clones are useful for some things. One of the things I use clones for is to keep and off site back up. So every once in a while, I update a clone on an external drive and I store in a location away from my computer. So that way my only backup isn't sitting there right next to my computer where both could get damaged say by water or fire.
So there's a look at the difference between using a Time Machine and making a backup clone. 'Til next time, this is Gary with MacMost Now.

Comments: 22 Responses to “MacMost Now 512: Time Machine Versus Cloning”

    2/6/11 @ 10:06 am

    I use Time Machine for backups and keep a copy offsite. If my MacBook were destroyed or stolen would I be able to use another MacBook or IMac to recover the Time Machine backup?

      2/6/11 @ 10:19 am

      Absolutely. That’s a primary function of Time Machine. For instance, on a new Mac you can use Migration assistant to recover all of your documents and applications from a TM backup from your failed Mac.

    G Tyler
    2/10/11 @ 1:22 pm

    I just upgraded my Time Capsule yesterday with a 2TB Western Digital Green drive. The ‘Green’ drives have variable rotational speeds and use less power. It’s a lot quieter than the ‘Black’ 1TB version that Apple included. We now have plenty of space to back up our four Macs. It wasn’t that hard to do, but I did destroy the rubber bottom – any idea where I could get a replacement for that? I have found that Migration Assistant works best if you directly connect the new Mac to the old Mac using an Ethernet cable. Of course, that assumes that the old one is still working fine. Maybe you could do a video of that process. Time Machine is a life safer and so easy to use.

    1/18/12 @ 7:03 am

    Hi Gary – don’t know why but my Time Machine has only back ups from today. I did have months of back ups but checking it today sees only a day. What happened to the old ones I had… it’s weird…

    Any advice mate? Love your videos too!


      1/18/12 @ 7:36 am

      Hard to say why. Are you sure the backups aren’t there? What, exactly, happens when you try to look at the timeline or go back further than today? Maybe your drive is out of space and that’s all there is room for — but you should have gotten a warning about that. What’s the size of your Time Machine drive relative to the size of the drive it is backing up?

    1/19/12 @ 4:33 am

    Well it’s kind of bizzare Gary. I just checked again tonight and it only has today’s back up? I use to have months worth. I checked the INFO on the ext drive I’m using and it says:

    Capacity 1 TB
    Available 452 GB
    Used 547 GB…

    It’s backing up my iMac HD which when I right click my Macintosh HD it says :

    Capacity 319.21 GB
    Available 185GB

    It also backs up my Photos ext drive which is 2 TB but has only 500GB used.

    So if it is backing up my Mac HD it backs up 319GB plus 500GB on the photos drive.

    Should I consider moving my photos drive to the smaller ext drive and then set up the Time Machine drive on the 2TB drive?

    Thanks Gary – love your newsletters and videos.


    1/19/12 @ 5:03 am

    update – I decided to use Disk Utility to check it out and the drive with the back ups reports a couple problems – “incorrect number of file hard links”

    So now I’m running repair. Lots of weird error messages – incorrect flags for director, and lots of orphaned directory inode.

    So now I’ve repaired it I can see if it backs up more then one day..?

      1/19/12 @ 7:42 am

      I doubt that will help but worth a try. Many error messages you will see are very very minor and don’t really cause problems.
      And yes, I would use the 2TB for backups and the 1TB for photos. Your largest drive should be your backup drive.

    1/19/12 @ 10:02 pm

    Thanks Gary – will change them over over the weekend. Oh boy…

    Thanks for your help mate.


    3/11/12 @ 1:20 am

    Hey Gary
    I right now have a macbook with a 500gb Hard drive and I bought a 1tb backup drive which I partitioned to have the time machine backups (700gb) and a second partition for storing videos and movies for easy access when connecting it to my TV. I was just wondering what happens to backups when the time machine drive eventually fills up? Does it delete the full backup that the drive took initially? (which would be stupid) or does it just delete the older incremental backups? (which would make more sense to me)

      3/11/12 @ 8:51 am

      When a TM drive gets close to full, then Time Machine handles it intelligently. It will delete older versions of files, always making sure at least the latest version of every file is there. The larger your drive, the more versions of old files you will have stored. In other words — you don’t even need to worry about this. TM will do the right thing.

        3/12/12 @ 8:16 pm

        Thanks for the info Gary keep up the great work! I as a mac user greatly appreciate the resources you have made available for us.

    4/30/12 @ 7:49 pm

    Gary, I had MacBook 2010 unibody that died. Got an Identical replacement. I would like to recover from my old Macbook’ s time machine external drive. Tried Migration assistant, lots of things not the same (desktop, music files etc,) Is a perfect recovery to before the crash possible. Help please!

      4/30/12 @ 8:19 pm

      Should be able to do a perfect recovery. Not sure why it didn’t work for you. Does the new one have the same OS (SL or Lion). Hard to help remotely.

        5/1/12 @ 9:20 am

        Yes OS X Lion 10.7.3 . I am surprised to learn there isn’t there a simple set procedure for this.

          5/1/12 @ 9:39 am

          Doing the default should get you a perfect recovery. I’ve done it before. Hard for me to say why it didn’t work in this case.

            5/1/12 @ 9:56 am

            I don’t even know what doing the default is. Could you please tell me? perhaps I have made an error. (it is the operator much more than the machine usually)

              5/1/12 @ 10:47 am

              By default, I mean just doing a plain restore. It should have worked.

    5/17/12 @ 11:32 am

    I bought 120GB SSD to upgrade my mac pro, and thinking what is the best? cloning or TIme machine?

      5/17/12 @ 11:48 am

      I would never do just cloning. I would do Time Machine, and then clone as a second (off-site?) backup.

    9/18/12 @ 1:43 pm

    Thanks Gary! One question: Is the timeMachine sitting on my external (WD Passport) drive, ‘bootable’? Or is my only option to be up and running on an alternate machine to use Migration Assistant and go through that process.

    Scenario: My machine is destroyed and I’ve got a deadline. I would like to run to a friend’s, hook up my ext drive and boot and finish the work (using CS4/preferences, everything). Is this doable with both clones and TM?


      9/18/12 @ 2:04 pm

      It is not bootable — it is an archive that includes multiple versions going back in time of your files. That’s much more useful. But yes, it will take more time to restore everything.

Comments Closed.