Mountain Lion: Backing Up to Multiple Time Machine Drives

| TMO Quick Tip

Time Machine is the backup system Apple built into OS X for the Mac, but has always felt a little limited — especially since it has always supported backing up your important files to only a single location. With the launch of OS X Mountain Lion, however, you can now choose multiple drives for Time Machine to use, and it’s easy to set up.

To add extra drives to your Time Machine backup routine, do this:

  • Connect the volume you want to add to your Time Machine backup schedule to your Mac. Time Machine supports hard drives and flash drives connected directly to your Mac as well as network volumes and Time Capsule.
  • Choose Apple menu > System Preferences.
  • Select the Time Machine Preference Pane.
  • Click Select Disk.

Choose the volume you want to add to your Time Machine backup routineChoose the volume you want to add to your Time Machine backup routine

  • Choose the volume you want to add to your backup routine, then click Use Disk.
  • You can choose to replace your original Time Machine backup, or to add the new volume to your routine. Click Use Both to add the new drive to your backup schedule.

Be sure to choose Use Both to add extra volumes to Time Machine's backup scheduleBe sure to choose Use Both to add extra volumes to Time Machine’s backup schedule

Time Machine will show you files from the volume it most recently used for backing up content. If you need to see files from a different backup location, just choose Time Machine > Browse Other Backup Disks.

Your Mac will rotate its backup schedule to include all of the volumes you add to Time Machine, which is great because that means you can easily have separate backups at work and home simply by keeping different hard drives at each location.

It’s also great for automatically backing up to more than one Time Machine volume at the same location. For example, you can backup to a Time Capsule on your own network, and have a second backup on a hard drive connected directly to your Mac — and you can never have too many backups of your important data.

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Comments

Wayne

I’m going to start downloading Mountain Lion the second I finish this post. Thanks for the tip Jeff, you totally rock!

Davy

This sounds like an awesome new feature. Heads up though, the OS update is a bit flakey. It worked for me after I did the magic rain dance! Seriously though, I made it half way through the update and it said that my HDD was not recognizable. Um, how did I launch the OS update if my hard drive was broken? I did a complete power off. And when it came back online everything resumed normally. Magic for the win!

Also, here is a list of some killer mac apps! http://goo.gl/PDC56

Joe

I have been backing up one Mac to two different HDs via Time Machine since Snow Leopard.
http://www.macworld.com/article/1146619/two_time_machines_backups.html

Wayne

I have been backing up one Mac to two different HDs via Time Machine since Snow Leopard.

I’ve also tried it under Snow Leopard and Lion. It works for two or three backups and then it decides that it needs to backup from scratch for some reason.  I have a 1TB drive in my MacBook Pro that’s nearly full and it can take a couple of days over WiFi to my Mac Mini/RAID home server when it screws up.  I gave up backing up while I’m traveling because of it. I’m glad they’re officially supporting multiple drives now.

Allister

Do you end up with identical backups on all the drives?

Jeff Gamet

Joe - While you have been able to use more than one hard drive for Time Machine backups, it’s always been a little bit of a hack since Apple wasn’t directly supporting the feature. With the multiple drive feature in Mountain Lion, all of your Time Machine drives are managed and included in your backup routine. No need to give all your TM drives the same name, and no need to work on keeping the backups in sync. I’m glad Apple finally realized we might want more than one drive in our TM backup routines.

DM

How do you use time machine to back up 2 HD onto 1 backup HD? For example my wife has a new imac with a 250 SSD boot drive and a 2 TB 2nd internal drive and I want to back up both to time machine.

Thanks,

dm

I have a time machine question not addressed above. How do you back up 2 drives onto 1 time machine backup HD.  For example an imac with 2 internal drives, 1 a 250 SSD and the 2nd a 2 TB internal HD.

thanks

MacInLew

I have a time machine question not addressed above. How do you back up 2 drives onto 1 time machine backup HD.? For example an imac with 2 internal drives, 1 a 250 SSD and the 2nd a 2 TB internal HD.

Unless you excluded one of the drives/volumes it should default to backing up both volumes. The problem is when it comes time to do a complete restore it will only restore the boot volume, not the non-boot volume. You can just copy the non-boot volume using the finder after the restore so it still works.

Lancashire-Witch

This Apple KB article says TM does not support external disks connected to an Airport Extreme.

No change, I think, from the Lion restrictions. So TM still feels limited to me in spite of now being able to use multiple disks.

I know TM can see properly formatted USB disks attached to an AE, and can use them. It’s just not supported, But I do it. I just wonder how much of a risk I’m taking.  Perhaps using Carbon Copy Cloner to backup up to an AE-attached disk is safer (And I’m much happier now CCC is no longer donation ware. Great stuff Mr Bombich).

Allister

I’ll ask my question again.

Do you end up with identical backups on all the drives?

For example, if backing up hourly and I plug in TM drive A for 5 hours, I’ll get (potentially) 5 versions. Then I swap it for TM drive B for 5 hours and I get (potentially) 5 newer versions. Are the first 5 versions also added to TM drive B?

If the answer is yes, then we have true multi-destination backups. If the answer is no then we have incremental backups ? where you’ll potentially need all of your backup drives to recover from a problem, making this less attractive for off-site backup.

Wayne

If the answer is yes, then we have true multi-destination backups.

Allister - I’ve been using it now for a few days (I did download Mountain Lion right away).  And I believe the answer to your question is yes (kind of).  If you use drive A for 5 hours, you’re going to get one complete backup plus 4 hours of incrementals.  If you then switch to drive B for 5 hours, you’re going to get another complete backup plus 5 hours of incrementals.  And if you switch back to drive A it will start doing incrementals from where it left off on drive A.  You’ll be able to restore from either drive, you won’t need both.  However, keep in mind that the most recently used drive is the more ideal drive to backup from (as it will have the most recent data).

Allister

Brilliant!

I guess to get the maximum flexibility you’d want to seed both backups one right after the other on a non-changing system (as much as possible). But other than that the only difference would be the oldest backups and even that wouldn’t matter after those ‘age’ out of the cycle.

Colour me impressed, Apple.

Now all we need is to be able to specify ‘backup sets’, and non-internal source drives and I could ditch most of my CrashPlan setup. (Yeah, CrashPlan isn’t going to be leaving me any time soon!)

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