Keep Time Machine HDD running

[MBP*]

My external is the chosen place where my backups are being stored. It gets annoying when the laptop needs to spin up the HDD to initiate the backup as everything on the laptop stops for a moment or two while that happens.

I'm also concerned of the unnecessary wear and tear by constant turn off and on. I'd much rather have it so that when I put my laptop to sleep, or wake it up, it should do the same.

I have already checked the box which says do not turn off HDD when possible, seems not to have made a difference for external devices?

 

[old-wiz]

External HDDs often spin down on their own - it seems to be a function of the drive itself and not accessible to he OS.

 

[370zulu]

Western Digital has a utility that you can use to set the sleep timer to "never". I found that even though I had my drive set to "never" that it still slept. In my case, turning off "Put hard disks to sleep when possible" resolved this and now my WD MyPassport USB drive does not go to sleep.

Have you checked the manufacturer website to see if this utility exists for your drive?