Why do CoreStorage external drives stay active after eject?

[benguild]

I've noticed that USB drives that are configured with CoreStorage can often still seem like they're writing data or spinning to various areas of the drive for a few minutes even after the volume is ejected and removed from the Desktop.

It doesn't seem that safe to disconnect them, but I may be wrong.

Does anyone know what's actually happening and if it's OK to remove them?

 

[grahamperrin]

Mysteries of Core Storage

… Does anyone know what's actually happening

Not me. Closed source Core Storage is too mysterious.

and if it's OK to remove them?

If none of the volumes associated with the physical drive are mounted: yes.