TrueNAS Sees the Disks but the Pool Will Not Mount
TrueNAS can detect every physical disk while the expected pool, datasets, or shares remain unavailable. Hardware detection is only the first layer; ZFS must also recognize a consistent vdev topology, usable labels, and a transaction history it can import.
Do not create a new pool, clear labels, initialize an offered disk, or repeatedly force the import. Record the detected topology and preserve every original member first.
What this condition means
A pool can fail to import or mount after power loss, controller or HBA changes, cabling events, updates, missing members, incomplete resilvering, or damage to metadata that describes the pool.
A disk shown as healthy may still contain unreadable regions or a different transaction history. Conversely, a member TrueNAS rejects may remain partly readable and important to recovery.
What to record
- TrueNAS edition and version
- Exact alerts, zpool status, and import output
- Pool name, vdev topology, RAIDZ level, and member count
- Bay, serial number, and detected device path for every drive
- Power, update, controller, replacement, resilver, detach, and import history
What not to do
- Create a new pool with the original members
- Clear or overwrite ZFS labels
- Force imports repeatedly or try random member combinations
- Move drives without documenting order and identity
- Run destructive tests against the only readable set
How ADR evaluates it
ADR determines whether the failure is device detection, vdev assembly, pool metadata, or dataset presentation. Member readability and ZFS identity are reviewed separately from the dashboard summary.
Stable logical failures may qualify for remote recovery. If a member is unstable, protected imaging precedes virtual pool reconstruction and dataset validation.
TrueNAS does not have to import the pool or mount its datasets first. ADR can access the members independently, establish the vdev topology and transaction state, and reconstruct from protected sources rather than experimenting on the active pool.
What happens next
A pool that will not mount can still retain recoverable datasets. The practical result depends on the vdev layout, readable member coverage, transaction consistency, and prior intervention.