RAID Volume Metadata: Snapshots or array capacity?
Pattern to record: Usable space is lower than expected from visible files.
Identify the storage layer
RAID metadata describes member order and array layout; it is separate from the file system inside the assembled volume. Record the controller, RAID level and physical drive order before import, rebuild or file-system repair. Snapshots are provided by a supported file system, storage pool or appliance feature; RAID alone does not establish snapshot support.
Protect data before repair
Do not initialise, reorder or rebuild uncertain members automatically. Deleting a snapshot or recreating a pool can remove a recovery path.
Evidence to check on the protected copy
- Record drive order and controller details and image unstable members before importing anything.
- Identify the NAS or storage software, its redundancy overhead and any supported snapshots or reservations.
Recovery and verification
If the checks support this cause, change only documented retention or allocation after confirming backup needs. Verification should cover array assembly, share access, redundancy state, restart and independent backup.
For an assessment of your RAID or NAS system, contact AEPC in Burswood or call 027 908 8880. Provide the model and the conditions that reproduce this problem. Workshop visits are by appointment.