Using Time Machine to back up an external drive

Whether you are working with thousands of photos, hours of video or semesters of lesson plans, securing and backing up your data remains critically important. If you have all of your data stored on the hard drive in your computer, this can be as easy as plugging in an external drive and setting up Time Machine (on a Mac). More likely, if you work with a lot of photos and video like I do, you have most of your data on an external drive. In an ideal world, you would back these up using some sort of Network Attached Storage RAID array. Coming from a newspaper environment, I know this isn’t always a reality. Sometimes all you have are a few externals lying around. Did you know that you can also set up Time Machine to back up one external drive (a media drive or capture scratch for example) to another external?


To do this, we will first go to our Apple Menu Items in the top left, and select the System Preferences. From there, open up Time Machine. Once in the Time Machine preferences panel, click on “Select Disk…” and choose the drive that will serve as the Time Machine backup.


Next, click on “Options…” in the lower right corner. This will bring up a window showing you what drives are excluded from the backup process. By default, your external drives will be here. Your backup drive is automatically excluded from the backup process, as it wouldn’t make sense to back it up to itself. However, we DO want to backup the Media drive, so let’s remove it from this list by selecting it and hitting the minus symbol as shown below.


As currently configured, Time Machine will try and backup the Media drive along with any internal hard drives. But we only want to backup the external Media drive, so let’s add our internal drives to this exclusion list. Click on the plus sign next to the minus sign you used earlier, and then find and exclude your internal drives.


In my case, I have two internal drives that I needed to exclude from Time Machine backup. Once complete, you can hit “Save” and then turn on Time Machine.