How do I STOP external drives waking up during Mac sleep?

[Sheza]

I have a couple external drives connected to my iMac. The first one is a Time Machine backup drive so I'm okay with it coming on in the middle of the night, as it's quiet. But my other external drive is quite loud and I don't want it coming on in the middle of the night.

I thought disabling 'Power Nap' would fix this but it hasn't.

How do I make sure that the drive sleeps forever and until I wake up the iMac again?

 

[Fishrrman]

Are the drives both powered by a "power block" that plugs into a wall outlet?

If so, I'd do this:
1. Buy a power strip with an on-off switch.
2. Plug both drives' power blocks into the power strip.
3. When I was done with the drives for the night, I'd drag the icons of both drives to the trash (to DISmount them from the desktop)
4. Once the drives were dismounted, reach down and flip the power strip to OFF.
5. The next morning, reach down and flip the power strip ON. The drives should power up and re-mount on their own.

 

[Sheza]

Are the drives both powered by a "power block" that plugs into a wall outlet?

If so, I'd do this:
1. Buy a power strip with an on-off switch.
2. Plug both drives' power blocks into the power strip.
3. When I was done with the drives for the night, I'd drag the icons of both drives to the trash (to DISmount them from the desktop)
4. Once the drives were dismounted, reach down and flip the power strip to OFF.
5. The next morning, reach down and flip the power strip ON. The drives should power up and re-mount on their own.

The small drive (Time machine) is not, the other drive is. That's a decent suggestion, thank you. I'm still wondering if there's a software fix for this.