Last week, I started getting errors from the external hard drive that I use for backing up my workstation. Since this is probably the sign of an impending failure, I ordered a new one immediately. Also, since external hard drives are lightweight and easy to steal, both the replacement and the drive being replaced are encrypted to protect their data.
In Linux, the most common solution for drive encryption is a combination of dm-crypt and LUKS. If you’re interested in setting up an encrypted drive yourself, you might find this walkthrough useful – I wrote it a few years ago, and still refer to it every time I need to refresh my memory on the command syntax for working with encrypted filesystems under Linux.