zhack(1)

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), zpool-features(5), ztest(1)