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Copyright 2013 Darik Horn <dajhorn@vanadac.com>. All rights reserved.

zhack - 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

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