Before SUN was bought by Oracle, OpenSolaris had ever newer versions and upgrading was just an
$ zpool upgrade rpool
away. But since then, the open source version of ZFS gained feature flags.
POOL FEATURE --------------- tank1 multi_vdev_crash_dump enabled_txg hole_birth extensible_dataset embedded_data bookmarks filesystem_limits
If you want to enable only one of these features, you may have already hit the
zpool upgrade can only upgrade one pool or all.
The way to go is to use
zpool set. Feature flags are options on the pool and
can also be listed with
$ zpool get all tank1 | grep feature tank1 feature@async_destroy enabled local tank1 feature@empty_bpobj active local tank1 feature@lz4_compress active local tank1 feature@multi_vdev_crash_dump disabled local ...
Enabling a feature, for example multi_vdev_crash_dump, would then be
$ zpool set feature@multi_vdev_crash_dump=enabled tank1
It will then disappear from the
zpool upgrade output and be set to enabled