ZFS feature upgrade

ZFS comes with quite a set of features. However when upgrading zfs, new features are not enabled by default for compatibility reasons.

This may be reported by zpool status:

linux # zpool status zpool1
  pool: zpool1
 state: ONLINE
status: Some supported and requested features are not enabled on the pool.
        The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
        the pool may no longer be accessible by software that does not support
        the features. See zpool-features(7) for details.
  scan: scrub repaired 0B in 00:17:51 with 0 errors on Sun Feb  9 00:41:52 2025
config:

        NAME                                            STATE     READ WRITE CKSUM
        zpool1                                          ONLINE       0     0     0
          nvme-Samsung_SSD_990_PRO_2TB_SERIAL1233456  ONLINE       0     0     0

errors: No known data errors

In order to get more information about possible new features you can use zpool upgrade:

linux # zpool upgrade 
This system supports ZFS pool feature flags.

All pools are formatted using feature flags.


Some supported features are not enabled on the following pools. Once a
feature is enabled the pool may become incompatible with software
that does not support the feature. See zpool-features(7) for details.

Note that the pool 'compatibility' feature can be used to inhibit
feature upgrades.

POOL  FEATURE
---------------
zpool1
      redaction_list_spill
      raidz_expansion
      fast_dedup
      longname
      large_microzap

You can add option -v to get more detailed information about available features and their release history.

Upgrading the feature set is as easy as this:

linux # zpool upgrade zpool1
This system supports ZFS pool feature flags.

Enabled the following features on 'zpool1':
  redaction_list_spill
  raidz_expansion
  fast_dedup
  longname
  large_microzap

linux # zpool upgrade zpool1
This system supports ZFS pool feature flags.

Pool 'zpool1' already has all supported and requested features enabled.