Extra disk drives make good bootable clones, and are perfect for both Time Machine backups, and quick syncs of critical files and folders from the Mac. Other than the expense and management effort, the only real issue with an external disk connected to your Mac is that crazy Mac jet leg.
No. More. Lag.
Almost every user with an external disk drive connected to their Mac experiences a little lag when using an Open… dialog box in an application. What’s going on? The external disk drive went to sleep, and when OS X goes into an Open… dialog box, it takes a few seconds for the drive to spin up to full speed from it’s hibernation vacation.
Of course, the lag is not apparent on most Mac notebooks which have an always on SSD, but it can affect connected disk drives, and even iMacs with built-in disk drives and connected disks have a similar lag. Here’s how to beat it.
Add Keep Drive Spinning to your Mac. This free utility does one thing that keeps each of your Mac’s connected drives away and running.
What Keep Drive Spinning does is simple. The utility creates an OS X launch agent which updates a hidden file on each disk drive every minute. That prevents the drive from going into sleep mode.
Not all disk drives are created equal, so Keep Drive Spinning treats them all the same. Some disk drives sleep after a few minutes, while others may behave according to settings in OS X’s System Preferences > Energy Saver. Most external disk drives do not.
By writing that little file to each disk drive every minute or so, the drive stays awake, and that prevents the lag from occurring when you click to open an Open… dialog box. What’s not to like? It’s free and it works.