zhack(1) libzpool debugging tool


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


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


-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.


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.


# zhack feature stat tank
        org.illumos:lz4_compress = 0
        com.delphix:async_destroy = 0
        com.delphix:empty_bpobj = 0
        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


This man page was written by Darik Horn <[email protected]>.