WD20EARX Offline data collection

One of my WD20EARX drives show a lot of the following smartmontools messages in syslog:

Device: /dev/sdb [SAT], is back in ACTIVE or IDLE mode, resuming checks (5
check skipped)

I assume this is part of the “Offline data collection” getting interrupted when the machine was shutdown during this offline test.

What sort of drive health data is collected during these “offline tests” ?

I run long selftests on a regular base, and they pass just fine. Since I know about these tests beeing in progress, I leave the machine powered up until the test has completed. So it’s sort of annoying to break these offline tests … it happens, because I never check if one of those offline tests is in progress before I shut the machine down. Does it  even matter?

I don’t think any public info is available on that. Did they tell you anything if you called them before?