ZFS pool-metadata recovery
The Meta Object Set, or MOS, describes pool-wide objects and dataset relationships. If required MOS blocks or their pointers are damaged, ZFS may detect all devices yet report that the pool metadata needed to open the pool is corrupt.
Understand the symptom
Pool labels provide configuration and uberblocks identify transaction-group roots. Recovery compares redundant labels and uberblocks, verifies vdev availability, and tests earlier consistent states. A rewind discards newer transaction groups, so a mountable pool is not proof that the latest data survived.
What you may see
OpenZFS reports that metadata required to open the pool is corrupt.
Device presence is not enough when the MOS or block-pointer tree is invalid.
An earlier transaction group may be consistent enough to open.
ZFS may traverse metadata and data to verify a candidate rewind state.
Protect the source
Writes after the selected recovery point are lost.
Extreme rewind searches farther back and has a larger potential data-loss window.
The -f flag overrides ownership protection; it does not prove another host is inactive.
Do this now
Prevent automatic imports, services, scrubs, rewinds, and writes across every host.
Save zpool import, status, events, labels, zdb output, device errors, GUIDs, and pool history.
Keep normal, special, log, cache, spare, removed, and replacement devices with original identity.
Work from array snapshots or member images before rewind or metadata repair attempts.
NEPFOSYS process
NEPFOSYS compares labels, uberblocks, transaction groups, MOS roots, and vdev availability.
Read-only imports and dry-run recovery points are evaluated on protected copies.
Recovered datasets, snapshots, file systems, and priority files are checked at the selected transaction state.
A clear next step
Start a case with the exact symptoms, incident timeline, prior attempts, encryption details, and the files that matter most. NEPFOSYS will route the case to the appropriate DFW intake or nationwide mail-in path.
Start with a case reviewQuestions, answered
It is the pool-wide Meta Object Set that describes datasets and other essential objects.
Yes. It rewinds to an earlier transaction group and discards newer transactions.
Only after preserving the pool and testing safer options on copies. Extended rewind can lose more recent data and is not guaranteed to work.
DFW local · Nationwide mail-in