WWN

Is there a reason we don't rely primarily on WWN changing to detect a disk
change at a particular location? I know it's not universally available, but
anything made in the last 15 or 20 years should have one if my research is
correct... Or is this just a case of inertia?

I'm looking at making ahci a little more resilient to transient outages,
and thought it might be best to key primarily off this and secondarily off
other changed information when that's not available. If I had a WWN, then
I'd know the disk that was gone for 500ms is the same one and I could
resume its operations and still detect that someone unplugged drive A and
plugged in drive B.

Warner