Add 'zpool status -e' flag to see unhealthy vdevs

[cmharr]

Motivation and Context

When very large pools are present, it can be laborious to find reasons for why a pool is degraded and/or where an unhealthy vdev is.

Description

This option filters out vdevs that are ONLINE and with no errors to make it easier to see where the issues are. Root and parents of unhealthy vdevs will always be printed.

How Has This Been Tested?

Sample vdev listings with '-e' option

• Single large pool

[root@iron5:~]# zpool list
	NAME    SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
	iron5   582T  89.7M   582T        -         -     0%     0%  1.00x    ONLINE  -
[root@iron5:~]# zpool status | wc -l
	97

• All vdevs healthy

[root@iron5:zfs2.2]# ./zpool status -e 
  pool: iron5 
 state: ONLINE 
  scan: scrub repaired 0B in 00:00:01 with 0 errors on Thu Jan 11 14:40:45 2024 
config:

	NAME        STATE     READ WRITE CKSUM
	iron5       ONLINE       0     0     0

errors: No known data errors

• ZFS errors

[root@iron5:zfs2.2]# ./zpool status -e 
  pool: iron5 
 state: ONLINE 
status: One or more devices has experienced an error resulting in data corruption.  Applications may be affected. action: Restore the file in question if possible.  Otherwise restore the entire pool from backup. see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A 
  scan: scrub repaired 24K in 00:00:01 with 1 errors on Thu Jan 11 14:41:27 2024 
config:

	NAME        STATE     READ WRITE CKSUM
	iron5       ONLINE       0     0     0
	  raidz2-5  ONLINE       1     0     0
	    L23     ONLINE       1     0     0
	    L24     ONLINE       1     0     0
	    L37     ONLINE       1     0     0

errors: 1 data errors, use '-v' for a list

• Vdev faulted

[root@iron5:zfs2.2]# ./zpool status -e 
   pool: iron5 state: DEGRADED 
status: One or more devices are faulted in response to persistent errors. Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Replace the faulted device, or use 'zpool clear' to mark the device repaired. 
  scan: scrub repaired 0B in 00:00:00 with 0 errors on Thu Jan 11 14:39:42 2024 
config:

	NAME        STATE     READ WRITE CKSUM
	iron5       DEGRADED     0     0     0
	  raidz2-6  DEGRADED     0     0     0
	    L67     FAULTED      0     0     0  too many errors

errors: No known data errors

• Vdev missing

[root@iron5:zfs2.2]# ./zpool status -e 
  pool: iron5 
 state: DEGRADED 
status: One or more devices could not be used because the label is missing or invalid.  Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Replace the device using 'zpool replace'. see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-4J 
  scan: scrub repaired 0B in 00:00:01 with 0 errors on Thu Jan 11 14:42:30 2024 
config:

	NAME        STATE     READ WRITE CKSUM
	iron5       DEGRADED     0     0     0
	  raidz2-6  DEGRADED     0     0     0
	    L67     UNAVAIL      3     1     0

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• [ X] New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• [X ] My code follows the OpenZFS code style requirements.
• [ X] I have updated the documentation accordingly.
• [ X] I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• [X ] All commit messages are properly formatted and contain Signed-off-by.

Signed-off-by: Cameron Harr harr1@llnl.gov

[behlendorf]

Looks good to me. Just one last request, let's update a few of the existing ZFS Test Suite test cases in tests/zfs-tests/tests/functional/cli_root/zpool_status/ to exercise this new option. It looks to me like zpool_status_002_pos.ksh could be trivially extended as well as zpool_status_003_pos.ksh. A new dedicated test would be a nice addition but I wouldn't consider it a must have.

[behlendorf]

Thanks, looks good!