zfs:spares
ZFS - Spares
ZFS has a special class of device known as a SPARE.
- Unlike normal devices, a SPARE belongs to the entire pool, not a single vdev.
- If any vdev in the pool suffers a device failure, and a SPARE is attached to the pool and available, the SPARE will automatically attach itself to the degraded vdev.
- Once attached to the degraded vdev, the SPARE begins receiving copies or reconstructions of the data that should be on the missing device.
- In traditional RAID, this would be called rebuilding.
- In ZFS, this is called resilvering.
IMPORTANT: SPARE devices do not permanently replace failed devices.
- They're just placeholders, intended to minimize the window during which a vdev runs degraded.
- Once the admin has replaced the failed device of the vdev, and the new permanent replacement device resilvers, the SPARE detaches itself from the vdev, and returns to pool-wide duty.
zfs/spares.txt · Last modified: 2021/10/13 00:55 by peter