Disks use

[mmkerc]

Recently I have noticed that one of my external hard drives is being accessed (i.e. hard drive is awake and r/w something) with no apparent activity. It is not Time Machine backing up, or a virus scan (via either Sophos, or Malwarebytes). I do not use iCloud Drive. When I go to activity monitor the CPU usage shows a Sudoku game that I leave open has used or is using 37% of CPU time. I did quit that program the the disk activity continued.

How can I find out what is causing/accessing the disk?

 

[Fishrrman]

There's a very long-running thread here already about this topic:
ssd swap - high usage of Terabytes Written

 

[mmkerc]

There's a very long-running thread here already about this topic:
ssd swap - high usage of Terabytes Written

I saw that thread and like you indicated it is very long. I did not think it applied to my issue as mine is with a external LaCie d2 technical hard drive, that essentially is a backup. By that I mean that I store ~3TB of native photos file, and my created native videos. The "active photos" and final movies are stored on a different drive.

That said I will read the full thread that you refer to and see if there is something in it that can help diagnose my issue.

 

[glenthompson]

Spotlight might be indexing it.

 

[mmkerc]

I saw that mentioned in another post and have block spotlight from indexing that drive and we'll see if that resolves the issue. I would like to know if there is an app that will tell me what is causing the activity on the hard drive though.

 

[Gnattu]

You can use iotop command to do that, but you have to disable SIP first as iotop uses dtrace