man/man1/zhack.1

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  21 .\" Copyright 2013 Darik Horn <dajhorn@vanadac.com>. All rights reserved.
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  23 .\" lint-ok: WARNING: sections out of conventional order: Sh SYNOPSIS
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  25 .Dd May 26, 2021
  26 .Dt ZHACK 1
  27 .Os
  28 .
  29 .Sh NAME
  30 .Nm zhack
  31 .Nd libzpool debugging tool
  32 .Sh DESCRIPTION
  33 This utility pokes configuration changes directly into a ZFS pool,
  34 which is dangerous and can cause data corruption.
  35 .Sh SYNOPSIS
  36 .Bl -tag -width Ds
  37 .It Xo
  38 .Nm zhack
  39 .Cm feature stat
  40 .Ar pool
  41 .Xc
  42 List feature flags.
  43 .
  44 .It Xo
  45 .Nm zhack
  46 .Cm feature enable
  47 .Op Fl d Ar description
  48 .Op Fl r
  49 .Ar pool
  50 .Ar guid
  51 .Xc
  52 Add a new feature to
  53 .Ar pool
  54 that is uniquely identified by
  55 .Ar guid ,
  56 which is specified in the same form as a
  57 .Xr zfs 8
  58 user property.
  59 .Pp
  60 The
  61 .Ar description
  62 is a short human readable explanation of the new feature.
  63 .Pp
  64 The
  65 .Fl r
  66 flag indicates that
  67 .Ar pool
  68 can be safely opened in read-only mode by a system that does not understand the
  69 .Ar guid
  70 feature.
  71 .
  72 .It Xo
  73 .Nm zhack
  74 .Cm feature ref
  75 .Op Fl d Ns | Ns Fl m
  76 .Ar pool
  77 .Ar guid
  78 .Xc
  79 Increment the reference count of the
  80 .Ar guid
  81 feature in
  82 .Ar pool .
  83 .Pp
  84 The
  85 .Fl d
  86 flag decrements the reference count of the
  87 .Ar guid
  88 feature in
  89 .Ar pool
  90 instead.
  91 .Pp
  92 The
  93 .Fl m
  94 flag indicates that the
  95 .Ar guid
  96 feature is now required to read the pool MOS.
  97 .
  98 .It Xo
  99 .Nm zhack
 100 .Cm label repair
 101 .Ar device
 102 .Xc
 103 Repair corrupted labels by rewriting the checksum using the presumed valid
 104 contents of the label.
 105 .El
 106 .
 107 .Sh GLOBAL OPTIONS
 108 The following can be passed to all
 109 .Nm
 110 invocations before any subcommand:
 111 .Bl -tag -width "-d dir"
 112 .It Fl c Ar cachefile
 113 Read
 114 .Ar pool
 115 configuration from the
 116 .Ar cachefile ,
 117 which is
 118 .Pa /etc/zfs/zpool.cache
 119 by default.
 120 .It Fl d Ar dir
 121 Search for
 122 .Ar pool
 123 members in
 124 .Ar dir .
 125 Can be specified more than once.
 126 .El
 127 .
 128 .Sh EXAMPLES
 129 .Bd -literal
 130 .No # Nm zhack Cm feature stat Ar tank
 131 for_read_obj:
 132         org.illumos:lz4_compress = 0
 133 for_write_obj:
 134         com.delphix:async_destroy = 0
 135         com.delphix:empty_bpobj = 0
 136 descriptions_obj:
 137         com.delphix:async_destroy = Destroy filesystems asynchronously.
 138         com.delphix:empty_bpobj = Snapshots use less space.
 139         org.illumos:lz4_compress = LZ4 compression algorithm support.
 140
 141 .No # Nm zhack Cm feature enable Fl d No 'Predict future disk failures.' Ar tank com.example:clairvoyance
 142 .No # Nm zhack Cm feature ref Ar tank com.example:clairvoyance
 143 .Ed
 144 .
 145 .Sh SEE ALSO
 146 .Xr ztest 1 ,
 147 .Xr zpool-features 7 ,
 148 .Xr zfs 8