zero-knowledge

setting zpool features

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 problem, that 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.

$ 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 active in zpool get.