Funny noises from external disks

[DanL]

I have a hard disk that I use as an external backup. It is mounted, but Spotlight has been told not to look at it. Nevertheless, every minute or two, I hear a clank, clunk, from that drive. Um, what's going on? Does the OS reach out to tweak an external disk every once in a while just for fun? I don't believe I see anything new on Activity Monitor when I hear these noises.

 

[Cory Cooper]

Hello,

Yes, that is normal. External drives that are mounted are "polled" by the Mac to verify connection status, and defrag files when idle. All of my externals have done this, and some are more audible than others. 3.5" desktop-class drives are more audible than 2.5" notebook-class drives. SSDs are silent obviously. You can see it on any external drive enclosure that has a status light, as it will blink during those operations.

Hope that helps.

C

 

[DanL]

OK, thank you. When I told Spotlight not to look at it, the activity on that disk decreased enormously. I figured the activity would cease entirely. But you're saying the OS is still keeping track of it. Good to know.

 

[Cory Cooper]

No worries.

Yes, disabling Spotlight will drop the activity to almost none, but it will still do a few things when it is connected and mounted.

C