In my system, the raid arrays seem to do periodic data scrubbing automatically. Maybe it’s something that’s part of Debian, or maybe it’s just a default kernel setting. I don’t think it helps much with data integrity – I think it helps more just by ensuring the continued functionality of the drives.
When it’s running, you can type cat /proc/mdstat
to see the progress.
That command will also show you if there is a failing drive, so that you can replace it.
I just hope federal services (like applying for a passport) don’t become Twitter-only after Trump appoints Elon as Secretary of Enshittification.