Is my drive running background media scans (BMS)? How often?

[HoneyBadger]

For SATA drives, check the output of smartctl -c /dev/sdX and look for a section like the following right at the top:

=== START OF READ SMART DATA SECTION ===
General SMART Values:
Offline data collection status:  (0x82) Offline data collection activity
                                        was completed without error.
                                        Auto Offline Data Collection: Enabled.

To try to read the SCSI page for the actual logged results, try:

sdparm --page=bc /dev/sdX

SAS drives, I would expect to return something. SATA, perhaps not.