The disk about to be wiped was no longer at the path I had written down

Background

An external 2TB drive was to be wiped and rebuilt as network storage. It had been identified earlier in the same session by its device path. By the time the destructive command was ready, the kernel had re-enumerated: that path now pointed at the machine's internal system disk, and the external drive had moved one letter along. Nothing announced the change. The old path still existed and still pointed at a real disk — just not the intended one.

Path

Symptom

a device path identified earlier in the same session

Assumption

assumed a path that names hardware stays pointing at that hardware

Measurement

re-confirmed model and capacity in the same step as the wipe

Decision

address disks by identity, and verify inside the destructive step

Response

The wipe was gated behind a re-confirmation of the drive's model and capacity, issued in the same step as the destructive command rather than as a separate earlier check. That gate reported a mismatch and the command never ran against the wrong disk. The rule that came out of it: a physical disk is never addressed by its kernel device letter in a destructive command. Device letters record assignment order, not identity — a reboot, a re-plug, or merely different enumeration timing reorders them. Either the identity is re-derived inside the same command, or the disk is addressed by a path that encodes identity rather than order.

Skill upgrade