Time Machine Backup


Today’s Question: I have an iMac and back up with a Time Machine and an external hard drive. Please discuss the role of a Time Machine in backup.

Tim’s Quick Answer: Time Machine provides a form of incremental backup, and is included as part of the Macintosh operating system. I consider Time Machine to be a good “extra” tool as part of a larger backup workflow, and I make use of Time Machine to backup my computers. However, I consider Time Machine to be a supplementary backup solution, not a primary solution.

More Detail: My personal preference is to employ a backup solution that creates an exact copy of my original data. So, for example, I have an external hard drive that I use for storing my photos, and another external hard drive that I use for all of my other key data. I use a synchronization software tool (GoodSync in my case, available at http://www.goodsync.com) to create a backup copy that is an exact copy of the source drive. This way, when I experience a hard drive failure, recovery is very straightforward.

With Time Machine you are creating an incremental backup. In other words, each time you backup with Time Machine you are only backing up files that have changed since the last backup. In addition, Time Machine maintains a number of copies of your files going back in time, based on the amount of free space on your hard drive.

So, with Time Machine you can literally go “back in time” if you realize you have deleted a file or modified a file in a way you didn’t intend. This can be very helpful, of course, but it doesn’t provide a solution for my primary goal, which is to have a backup that is an exact copy of my master hard drive.

In my case I keep my photos and most of my key data on external hard drives. I then use synchronization software to create a backup copy of those drives, generally to at least two backup drives. To me this is a relatively ideal solution.

Of course, one of the problems with a synchronization backup is that it also duplicates your mistakes. If you erase a photo from your primary storage drive, a synchronization backup will also erase the photo from the backup drive. In most cases you can disable the removal of files in the synchronization process, provided you have adequate storage capacity on your backup drive.

I do, however, still employ Time Machine as part of my larger backup solution. This allows me to create regular backup copies of active files on my computer’s internal hard drive. In general that doesn’t impact my photography workflow, but since Time Machine is so easy to implement and because it helps overcome scenarios such as when you inadvertently erase or modify a file, I consider it an important part of my overall backup workflow.

So, whenever I’ve performed any significant work (and sometimes even after only insignificant work!) I will perform a synchronization backup of my external hard drives and a Time Machine backup of my internal hard drive. In my mind, any solution that is easy to implement and provides safeguards in your workflow is a good solution. Time Machine along with a synchronization backup certainly meet those criteria in my mind.