Site logo
DuPage Apple User Group
Members Helping Members Since 1979!


17 Jan 2011
Recently on the DAUG email discussion list,, there has been some discussion about backups. Time Machine makes multiple copies of backups. Great for accessing something you’ve updated seven times since you deleted the information you needed a month ago. However, a Time Machine backup is not a bootable backup. If you machine goes kablooie, you need to boot from your system disc (i.e. Snow Leopard) and select the option to restore from a Time Machine backup to restore on to a replacement machine. Of course, this will wipe out the drive on the replacement machine. Not a problem if the replacement machine is truly a replacement machine, but not a good idea if the replacement machine is simply borrowed while your machine is being repaired.

For a bootable backup, consider a program like Carbon Copy Cloner (CCC) or SuperDuper (SD). CCC is donation-ware. If you like it, they ask that you donate to support it. SD is a purchase product. SD has stated that they charge for their software mostly because of the support they provide. SD says nothing is more important than support when you need to restore from a SD backup. A bootable copy of this nature is a complete and exact copy of your boot drive. You can even setup a schedule to make a regular, timed, backup of your boot drive so it stays current.

Why would you want a bootable backup? The beauty is if your machine dies, you simply borrow (or use) another machine and boot from your bootable backup and everything is exactly where it should be without messing up the borrowed machine.

Holes? Time Machine can easily backup multiple source volumes into a single Time Machine backup. However if you have more than one drive hooked to your computer, a bootable backup only backs up the boot drive.

The beauty is that you can actually have both types of back on an external HD. However if you do so, it is recommended that you partition the external HD and use one partition for your bootable backup, and one partition for your Time Machine backups. For the bootable partition, make sure the partition has enough space to match all of the used space of your normal boot drive, plus a fudge factor for future growth. How do you know how much space you are using of your boot drive? Select the boot drive in the Finder and do a File (menu) then Get Info and look at the used space. Then simply point Time Machine to the second partition and you’re all set.

But continuing the discussion a little further, a backup sitting next to your computer is no good if your house burns down or floods, is a victim of theft or some type of disaster like that. In that case, you need an offsite backup. For an offsite backup, consider getting two more external HD’s (three in total).

Your backup strategy then turns into something like this:

  • You make a CCC or SD back to one of the external HD’s. You take that backup off site (office, lock box, vacation home, trusted neighbor, etc.).
  • Once the first copy is offsite, you start making the second backup copy. Do this for a week, then swap the two offsite drives. You now have a secure offsite for disaster recovery. Worst case you lose about a week’s worth of data. Much better than a total loss of data.
  • For the third external HD, use that one for a Time Machine backup. That way you can still have a multi-copy backup so you can restore that deleted paragraph from a month ago. The third drive stays local all the time.

If the worst case scenario occurs, yes you lose the backup from a month ago, but you’ll be so happy just to have the offsite copy that you probably won’t mind that. Besides, 99.999% of the time, Time Machine will be the only backup that you’ll ever need to access. But for that 0.001% of the time…

Another option is cloud backup. Cloud backup is where the backup files are stored online or “in the cloud”. You don’t need to worry about backing up the backup because that is part of the cloud service. You can usually access your files from one or many computers. Usually 100% encrypted so your data remains entirely safe. (There is no way I or anybody else can see your data.) The down side is that you are backing up (and restoring?) your files over your internet connection. This can be slow depending on your internet connection. Remember, when backing up, this is your upload speed, which is often 10 times slower than your download speed.

Apple provides a very basic (bare minimum?) service with iDisk which is part of MobileMe. There are a growing number of independent services out there. Carbonite and Mozy are a couple of the brand name services. Bryan Pearce of DAUG (and Deneb Corporation) reports his company offers a product called CrashPlan Pro.  It just works. Select the directory or directories you want backed up for example, your home directory and CrashPlan looks for internet availability and will keep your data backed up in the background.  This solution works very well for laptops in addition to desktop machines.  You also don’t have to worry about your internet connection feeling slow due to the backup process.  CrashPlan does most of its work when your internet connection is idle or based on use preferences you can control.  The best part is, you don’t even know it’s working until you need it.

Ed Danley

No comments

Leave a Reply

You must be logged in to post a comment.

Powered by WordPress