What is the purpose of the certify operation against a local disk drive?

Formatting a drive creates a filesystem structure at the logical level, which is a distinct operation from certify's low-level physical sector testing.

The certify operation writes test patterns across every sector of the target disk to validate the physical integrity of the media, which is a destructive process that overwrites and erases all existing data. This makes certify a data-destructive maintenance tool that should only be run on a disk that has already been backed up or is being repurposed.

While certify does exercise sectors as part of its process, the defining and operationally critical characteristic is that it is a destructive write operation - not a passive, read-only integrity scan.

Device quorum is a cluster or storage management concept used to arbitrate access between nodes, and is entirely unrelated to the certify disk operation.