So basically someone told you that the external SSD needs to be powered on, and connected to an offline host to do its background scrubbing?
This part I don't understand. My experience in IT has been:
- Data scrubbing is something your host (OS) does, as a software function
- Data scrubbing is something your HW RAID or disk firmware does (maybe kicked off by an scheduling app)
- Some forms of scrubbing are "dumb", in that they wait until the drive has no traffic. If there's disk activity, it stops scrubbing since scrubbing robs your disk performance (it's reading data in the background)
I would check what docs are available for this particular drive, to confirm that's what supposed to happen. Scrubbing should run faster with no system load, because it's run as a low-priority task. The question is there some interval before the scrubbing kicks off, or you need some tool to send the SSD instructions to start scrubbing?