ReadMe.c

   1 /*
   2  * mdctl - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001 Neil Brown <neilb@cse.unsw.edu.au>
   5  *
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2 of the License, or
  10  *    (at your option) any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *    Author: Neil Brown
  22  *    Email: <neilb@cse.unsw.edu.au>
  23  *    Paper: Neil Brown
  24  *           School of Computer Science and Engineering
  25  *           The University of New South Wales
  26  *           Sydney, 2052
  27  *           Australia
  28  */
  29
  30 #include "mdctl.h"
  31
  32 char Version[] = "mdctl - v0.2 - 06 June 2001\n";
  33 /*
  34  * File: ReadMe.c
  35  *
  36  * This file contains general comments about the implementation
  37  * and the various usage messages that can be displayed by mdctl
  38  *
  39  * mdctl is a single program that can be used to control Linux md devices.
  40  * It is intended to provide all the functionality of the mdtools and
  41  * raidtools but with a very different interface.
  42  * mdctl can perform all functions without a configuration file.
  43  * There is the option of using a configuration file, but not in the same
  44  * way that raidtools uses one
  45  * raidtools uses a configuration file to describe how to create a RAID
  46  * array, and also uses this file partially to start a previously
  47  * created RAID array.  Further, raidtools requires the configuration
  48  * file for such things as stopping a raid array which needs to know
  49  * nothing about the array.
  50  *
  51  * The configuration file that can be used by mdctl lists two
  52  * different things:
  53  * 1/ a mapping from uuid to md device to identify which arrays are
  54  *    expect and what names (numbers) they should be given
  55  * 2/ a list of devices that should be scanned for md sub-devices
  56  *
  57  *
  58  */
  59
  60 /*
  61  * mdctl has 4 major modes of operation:
  62  * 1/ Create
  63  *     This mode is used to create a new array with a superbock
  64  *     It can progress in several step create-add-add-run
  65  *     or it can all happen with one command
  66  * 2/ Assemble
  67  *     This mode is used to assemble the parts of a previously created
  68  *     array into an active array.  Components can be explicitly given
  69  *     or can be searched for.  mdctl (optionally) check that the components
  70  *     do form a bonafide array, and can, on request, fiddle superblock
  71  *     version numbers so as to assemble a faulty array.
  72  * 3/ Build
  73  *     This is for building legacy arrays without superblocks
  74  * 4/ Manage
  75  *     This is for odd bits an pieces like hotadd, hotremove, setfaulty,
  76  *     stop, readonly,readwrite
  77  *     If an array is only partially setup by the Create/Assemble/Build
  78  *     command, subsequent Manage commands can finish the job.
  79  */
  80
  81 char short_options[]="-ABCDEhVvc:l:p:n:x:u:c:sarfRSow";
  82 struct option long_options[] = {
  83     {"manage",    0, 0, '@'},
  84     {"assemble",  0, 0, 'A'},
  85     {"build",     0, 0, 'B'},
  86     {"create",    0, 0, 'C'},
  87     {"detail",    0, 0, 'D'},
  88     {"examine",   0, 0, 'E'},
  89     /* after those will normally come the name of the md device */
  90     {"help",      0, 0, 'h'},
  91     {"version",   0, 0, 'V'},
  92     {"verbose",   0, 0, 'v'},
  93
  94     /* For create or build: */
  95     {"chunk",     1, 0, 'c'},
  96     {"rounding",  1, 0, 'c'}, /* for linear, chunk is really a rounding number */
  97     {"level",     1, 0, 'l'}, /* 0,1,4,5,linear */
  98     {"parity",    1, 0, 'p'}, /* {left,right}-{a,}symetric */
  99     {"layout",    1, 0, 'p'},
 100     {"raid-disks",1, 0, 'n'},
 101     {"spare-disks",1,0, 'x'},
 102
 103     /* For assemble */
 104     {"uuid",      1, 0, 'u'},
 105     {"config",    1, 0, 'c'},
 106     {"scan",      0, 0, 's'},
 107     {"force",     0, 0, 'f'},
 108     /* Management */
 109     {"add",       0, 0, 'a'},
 110     {"remove",    0, 0, 'r'},
 111     {"fail",      0, 0, 'f'},
 112     {"set-faulty",0, 0, 'f'},
 113     {"run",       0, 0, 'R'},
 114     {"stop",      0, 0, 'S'},
 115     {"readonly",  0, 0, 'o'},
 116     {"readwrite", 0, 0, 'w'},
 117
 118     {0, 0, 0, 0}
 119 };
 120
 121 char Usage[] =
 122 "Usage: mdctl --help\n"
 123 "  for help\n"
 124 ;
 125
 126 char Help[] =
 127 "Usage: mdctl --create device options...\n"
 128 "       mdctl --assemble device options...\n"
 129 "       mdctl --build device options...\n"
 130 "       mdctl --detail device\n"
 131 "       mdctl --examine device\n"
 132 "       mdctl device options...\n"
 133 " mdctl is used for controlling Linux md devices (aka RAID arrays)\n"
 134 " For detail help on major modes use, e.g.\n"
 135 "         mdctl --assemble --help\n"
 136 "\n"
 137 "Any parameter that does not start with '-' is treated as a device name\n"
 138 "The first such name is normally the name of an md device.  Subsequent\n"
 139 "names are names of component devices."
 140 "\n"
 141 "Available options are:\n"
 142 "  --create      -C   : Create a new array\n"
 143 "  --assemble    -A   : Assemble an existing array\n"
 144 "  --build       -B   : Build a legacy array without superblock\n"
 145 "  --detail      -D   : Print detail of a given md array\n"
 146 "  --examine     -E   : Print content of md superblock on device\n"
 147 "  --help        -h   : This help message or, after above option,\n"
 148 "                       mode specific help message\n"
 149 "  --version     -V   : Print version information for mdctl\n"
 150 "  --verbose     -v   : Be more verbose about what is happening\n"
 151 "\n"
 152 " For create or build:\n"
 153 "  --chunk=      -c   : chunk size of kibibytes\n"
 154 "  --rounding=        : rounding factor for linear array (==chunck size)\n"
 155 "  --level=      -l   : raid level: 0,1,4,5,linear.  0 or linear for build\n"
 156 "  --paritiy=    -p   : raid5 parity algorith: {left,right}-{,a}symmetric\n"
 157 "  --layout=          : same as --parity\n"
 158 "  --raid-disks= -n   : number of active devices in array\n"
 159 "  --spare-disks= -x  : number of spares (eXtras) to allow space for\n"
 160 "\n"
 161 " For assemble:\n"
 162 "  --uuid=       -u   : uuid of array to assemble. Devices which don't\n"
 163 "                       have this uuid are excluded\n"
 164 "  --config=     -c   : config file\n"
 165 "  --scan        -s   : scan config file for missing information\n"
 166 "  --force       -f   : Assemble the array even if some superblocks appear out-of-date\n"
 167 "\n"
 168 " General management:\n"
 169 "  --add         -a   : add, or hotadd subsequent devices\n"
 170 "  --remove      -r   : remove subsequent devices\n"
 171 "  --fail        -f   : mark subsequent devices a faulty\n"
 172 "  --set-faulty       : same as --fail\n"
 173 "  --run         -R   : start a partially built array\n"
 174 "  --stop        -S   : deactive array, releasing all resources\n"
 175 "  --readonly    -o   : mark array as readonly\n"
 176 "  --readwrite   -w   : mark array as readwrite\n"
 177 ;
 178
 179
 180 char Help_create[] =
 181 "Usage:  mdctl --create device -chunk=X --level=Y --raid-disks=Z devices\n"
 182 "\n"
 183 " This usage will initialise a new md array and possibly associate some\n"
 184 " devices with it.  If enough devices are given to complete the array,\n"
 185 " the array will be activated.  Otherwise it will be left inactive\n"
 186 " to be competed and activated by subsequent management commands.\n"
 187 "\n"
 188 " As devices are added, they are checked to see if they contain\n"
 189 " raid superblock or filesystems.  They are also check to see if\n"
 190 " the variance in device size exceeds 1%.\n"
 191 " If any discrepancy is found, the array will not automatically\n"
 192 " be run, though the presence of a '--run' can override this\n"
 193 " caution.\n"
 194 "\n"
 195 " The General management options that are valid with --create are:\n"
 196 "   --run   : insist of running the array even if not all devices\n"
 197 "             are present or some look odd.\n"
 198 "   --readonly: start the array readonly - not supported yet.\n"
 199 "\n"
 200 ;
 201
 202 char Help_build[] =
 203 "Usage:  mdctl --build device -chunk=X --level=Y --raid-disks=Z devices\n"
 204 "\n"
 205 " This usage is similar to --create.  The difference is that it creates\n"
 206 " a legacy array with a superblock.  With these arrays there is no\n"
 207 " different between initially creating the array and subsequently\n"
 208 " assembling the array, except that hopefully there is useful data\n"
 209 " there in the second case.\n"
 210 "\n"
 211 " The level may only be 0 or linear.\n"
 212 " All devices must be listed and the array will be started once complete.\n"
 213 ;
 214
 215 char Help_assemble[] =
 216 "Usage: mdctl --assemble device options...\n"
 217 "       mdctl --assemble --scan options...\n"
 218 "\n"
 219 "This usage assembles one or more raid arrays from pre-existing\n"
 220 "components.\n"
 221 "For each array, mdctl needs to know the md device, the uuid, and\n"
 222 "a number of sub devices.  These can be found in a number of ways.\n"
 223 "\n"
 224 "The md device is either given before --scan or is found from the\n"
 225 "config file.  In the latter case, multiple md devices can be started\n"
 226 "with a single mdctl command.\n"
 227 "\n"
 228 "The uuid can be given with the --uuid option, or can be found in\n"
 229 "in the config file, or will be taken from the super block on the first\n"
 230 "subdevice listed on the command line or in a subsequent --add command.\n"
 231 "\n"
 232 "Devices can be given on the --assemble command line, on subsequent\n"
 233 "'mdctl --add' command lines, or from the config file.  Only devices\n"
 234 "which have an md superblock which contains the right uuid will be\n"
 235 "considered for any device.\n"
 236 "\n"
 237 "The config file is only used if explicitly named with --config or\n"
 238 "requested with --scan.  In the later case, '/etc/md.conf' is used.\n"
 239 "\n"
 240 "If --scan is not given, then the config file will only be used\n"
 241 "to find uuids for md arrays.\n"
 242 "\n"
 243 "The format of the config file is:\n"
 244 "   not yet documented\n"
 245 "\n"
 246 ;