Choosing a Time Machine Backup Drive
There are several issues to consider in choosing a drive for Time Machine:
- Capacity for current and future needs;
- Performance: a slow drive can interrupt your work or take a very long time to finish. A USB drive is therefore a poor choice;
- Convenience, location, etc: internal or external, at your Mac or in a closet, etc.
These issues are discussed below.
Capacity of the Time Machine backup drive PERMALINK
Time Machine keeps a backup of everything that you don’t explicitly exclude.
In addition, Time Machine keeps versions of files as they change. Lacking enough space, Time Machine will forget about older versions to make space for newer versions, so be sure to provide a large enough backup volume to get maximal benefit of the versioning feature.
A figure of 30% should be considered an absolute minimum, double the space of your data is ideal eg a 2TB backup drive for 1TB of data.
Note that this guideline is about how much data you actually have. For example, you might have a 2TB drive with only 200GB of data. You therefore could quite reasonably use a 500GB backup drive for Time Machine, at least until such a time as your data grows much larger.
Which hard drive?
Most Macs except the Mac Pro have limited options because only one drive can be installed internally (MacBook Pro users can skirt this limitation with a special bracket, and by removing the internal DVD drive).
The Mac Pro has four internal drive bays, and in addition the lower optical bay can be used for a boot drive (an SSD is best). With four internal bays freed up for data, an ideal option is to dedicate one bay to an internal 2TB hard drive.
Here is a shopping cart with recommended drives for a Time Machine backup. I strongly recommend a 2TB drive, because the cost difference over a 1TB drive is not great; it’s a better investment.
Whatever you do, do not get a USB-only drive! It can be used, but it’s painfully slow for any significant amount of data. Choose “quad interface” drives for flexibility in attaching via the fastest possible means for your computer.
Users with a Mac Pro and large amounts of data should be using either fast internal SATA drives, or eSATA.
Apple’s Time Capsule
Apple’s Time Capsule is a decent option, but its price is relatively high. The Time Capsule can also backup another Mac, which brings its relative price down.
Time Capsule has the appeal of being available on a network, so you can locate it away from your Mac. However, I do not recommend using a wireless network for this purpose; it is horribly slow and unreliable. Use ethernet (wired) and performance will be reasonably fast.