Best Way to Power Off External Hard Drive

Question

When powering off an external hard drive with a usb cable, a data cable, and an on/off switch, am I supposed to press the switch or to pull the usb cable first? And which way when powering it on? I'm asking because my hard drives seem to spin down in a more controlled way when I pull the usb cable first.

Solution

The safest way would be:

1. Safely eject the USB device to be sure there are no reads/writes queued and all mounts and locks are released
2. Remove the USB cable
3. Power down the device using your on/off switch (If the device spins itself down after inactivity, wait for this to occur first). It doesn't really matter too much, the drive will park the heads on power off anyway. Note that a lot of external drives are now completely powered by USB, so this step is negated.

In reality, most people neglect steps 1 and 2, and most of the time it won't cause any problem. If you're in the middle of a write though, this could cause corruption.

Edit: Apologies, missed your part about how to turn it on. Effectively the reverse, but of course without Step 1.

Comments

[UTF-8]

Does pressing the "Power off the drive" in gnome-disks do any benefit?

[AFH]

@UTF-8 - I usually eject from Nautilus, and this has never caused a problem, but if I happen to be running Disks at the time then I will use this, If there are no volumes mounted, there should be no need, unless you have been partition editing.