You can request a more detailed health summary by using the -v option. For example:
# zpool status -v tank pool: tank state: DEGRADED status: One or more devices could not be opened. Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Attach the missing device and online it using 'zpool online'. see: http://www.sun.com/msg/ZFS-8000-2Q scrub: none requested config: NAME STATE READ WRITE CKSUM tank DEGRADED 0 0 0 mirror DEGRADED 0 0 0 c1t0d0 FAULTED 0 0 0 cannot open c1t1d0 ONLINE 0 0 0 errors: No known data errors
This output displays a complete description of why the pool is in its current state, including a readable description of the problem and a link to a knowledge article for more information. Each knowledge article provides up-to-date information on the best way to recover from your current problem. Using the detailed configuration information, you should be able to determine which device is damaged and how to repair the pool.
In the above example, the faulted device should be replaced. After the device is replaced, use the zpool online command to bring the device back online. For example:
# zpool online tank c1t0d0 Bringing device c1t0d0 online # zpool status -x all pools are healthy
If the autoreplace property is on, you might not have to online the replaced device.
If a pool has an offlined device, the command output identifies the problem pool. For example:
# zpool status -x pool: tank state: DEGRADED status: One or more devices has been taken offline by the adminstrator. Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Online the device using 'zpool online' or replace the device with 'zpool replace'. scrub: none requested config: NAME STATE READ WRITE CKSUM tank DEGRADED 0 0 0 mirror DEGRADED 0 0 0 c1t0d0 ONLINE 0 0 0 c1t1d0 OFFLINE 0 0 0 errors: No known data errors
The READ and WRITE columns provides a count of I/O errors seen on the device, while the CKSUM column provides a count of uncorrectable checksum errors that occurred on the device. Both of these error counts likely indicate potential device failure, and some corrective action is needed. If non-zero errors are reported for a top-level virtual device, portions of your data might have become inaccessible.
The errors: field identifies any known data errors.
In the example output above, the offlined device is not causing data errors.
For more information about diagnosing and repairing faulted pools and data, see Chapter 11, ZFS Troubleshooting and Pool Recovery.