Case study: recovery of a corrupted 12 TB multi-device pool (github.com)

A GitHub issue documents a case study of recovering a severely corrupted 12 TB btrfs multi-device pool after a hard power cycle left core trees inconsistent. The author reports that `btrfs check --repair` entered an infinite 46,000+ commit loop with no progress, and final recovery required 14 custom C tools using the internal `btrfs-progs` API, with only ~7.2 MB of data loss from 4.59 TB. The post also proposes nine potential upstream changes and publishes a reference tool set for similar incidents.