NAME

       zhack - libzpool debugging tool

DESCRIPTION

       This  utility pokes configuration changes directly into a ZFS pool, which is dangerous and
       can cause data corruption.

SYNOPSIS

       zhack [-c cachefile] [-d dir] <subcommand> [arguments]

OPTIONS

       -c cachefile

              Read the pool configuration from the cachefile, which  is  /etc/zfs/zpool.cache  by
              default.

       -d dir

              Search for pool members in the dir path. Can be specified more than once.

SUBCOMMANDS

       feature stat pool

              List feature flags.

       feature enable [-d description] [-r] pool guid

              Add  a  new feature to pool that is uniquely identified by guid, which is specified
              in the same form as a zfs(8) user property.

              The description is a short human readable explanation of the new feature.

              The -r switch indicates that pool can be safely  opened  in  read-only  mode  by  a
              system that does not have the guid feature.

       feature ref [-d|-m] pool guid

              Increment the reference count of the guid feature in pool.

              The -d switch decrements the reference count of the guid feature in pool.

              The -m switch indicates that the guid feature is now required to read the pool MOS.

EXAMPLES

       # zhack feature stat tank

       for_read_obj:
            org.illumos:lz4_compress = 0
       for_write_obj:
            com.delphix:async_destroy = 0
            com.delphix:empty_bpobj = 0
       descriptions_obj:
            com.delphix:async_destroy = Destroy filesystems asynchronously.
            com.delphix:empty_bpobj = Snapshots use less space.
            org.illumos:lz4_compress = LZ4 compression algorithm support.

       # zhack feature enable -d 'Predict future disk failures.' \
           tank com.example:clairvoyance

       # zhack feature ref tank com.example:clairvoyance

AUTHORS

       This man page was written by Darik Horn <dajhorn@vanadac.com>.

SEE ALSO

       splat(1), zfs(8), zpios(1), zpool-features(5), ztest(1)