TODO

   1  - add 'name' field to metadata type and use it.
   2  - use validate_geometry more
   3  - metadata should be able to check/reject bitmap stuff.
   4
   5 DDF:
   6   Three new metadata types:
   7     ddf - used only to create a container.
   8     ddf-bvd - used to create an array in a container
   9     ddf-svd - used to create a secondary array from bvds.
  10
  11   Usage:
  12     mdadm -C /dev/ddf1 /dev/sd[abcdef]
  13     mdadm -C /dev/md1 -e ddf /dev/sd[a-f]
  14     mdadm -C /dev/md1 -l container /dev/sd[a-f]
  15
  16         Each of these create a new ddf container using all those
  17         devices.  The name 'ddf*' signals that ddf metadata should be used.
  18         '-e ddf' only supports one level - 'container'.  'container' is only
  19         supported by ddf.
  20
  21     mdadm -C /dev/md1 -l0 -n4 /dev/ddf1 # or maybe not ???
  22     mdadm -C /dev/md1 -l1 -n2 /dev/sda /dev/sdb
  23         If exactly one device is given, and it is a container, we select
  24         devices from that container.
  25         If devices are given that are already in use, they must be in use by
  26         a container, and the array is created in the container.
  27         If devices given are bvds, we slip under the hood to make
  28           the svd arrays.
  29
  30     mdadm -A /dev/ddf ......
  31         base drives make a container.  Anything in that container is started
  32          auto-read-only.
  33          if /dev/ddf is already assembled, we assemble bvds and svds inside it.
  34
  35
  36 2005-dec-20
  37   Want an incremental assembly mode to work nicely with udev.
  38   Core usage would be something like
  39        mdadm --incr-assemble /dev/newdevice
  40   This would
  41      - examine the device to determine  uuid etc.
  42      - look for a match in /etc/mdadm.conf, abort if not found
  43      - find that device and collect current contents
  44      - perform an 'assemble' analysis to make sure we have the best set of devices.
  45      - remove or add devices as appropriate
  46      - possibly start the array if it was complete
  47
  48    Other usages could involve
  49      - specify which array to auto-add to.
  50        This requires an existing array for uuid matching... is there any point?
  51
  52      -
  53
  54
  55 2004-june-02
  56   * Don't print 'errors' flag, it is meaningless. DONE
  57   * Handle new superblock format
  58   * create device file on demand, particularly partitionable devices. DONE
  59       BUT figure a way to create the partition devices.
  60               auto=partN
  61   * Use Event: interface to listen for events. DONE, untested
  62   * Make sure mdadm -As can assemble multi-level RAIDs ok.
  63   * --build to build raid1 or multipath arrays
  64        clean or not ???
  65
  66 ----------------------------------------------------------------------------
  67 * mdadm --monitor to monitor failed multipath paths and re-instate them.
  68
  69 * Maybe make "--help" fit in 80x24 and have a --long-help with more info. DONE
  70
  71
  72 * maybe "missing" instead of <bold>missing</> in doco DONE
  73 * possibly wait for resync to start, or even finish while assembling.- NO
  74
  75 * -Db should have a devices= entry if possible. - DONE
  76 * when assembling multipath arrays, ignore any error indicators. - DONE
  77 * rationalise --monitor usage:
  78      mdadm --monitor
  79   doesn't do as expected. DONE
  80
  81 * --assemble could have a --update option. - DONE
  82   following word can be:
  83         sparc2.2
  84         super-minor
  85
  86 * mdadm /dev/md11, where md11 is raid0 can segfault, particularly when looking in the
  87    [UU_UUU] string ... which doesn't exist !
  88 It should be more sensible.  DONE
  89
  90 Example:
  91
  92 from  Raimund Sacherer <raimund.sacherer@ngit.at>
  93
  94 mke2fs -m0 -q /dev/ram1 300
  95 mount -n -t ext2 /dev/ram1 /tmp
  96 echo DEVICE /dev/[sh]* >> /tmp/mdadm.conf
  97 mdadm -Esb /dev/[sh]* 2>/dev/null >> /tmp/mdadm.conf
  98 mdadm -ARsc /tmp/mdadm.conf
  99 umount /tmp
 100
 101
 102 ?? Allow -S /dev/md? - current complains subsequent not a/d/r - DONE
 103
 104 * new "Query" mode to subsume --detail and --examine.
 105    --query or -Q, takes a device and tells if it is an MD device,
 106    and also tells in a raid superblock is found.
 107  DONE
 108
 109 * write mdstat.c to parse /proc/mdstat file
 110    Build list of arrays:  name, rebuild-percent
 111   DONE
 112
 113 * parse /proc/partitions and map major/minor into /dev/* names,
 114   and use that for default DEVICE list ????
 115
 116 * --detail --scan to read /proc/mdstat, and then iterate over these,
 117     but assume --brief.  --verbose can override
 118     check each subdevice to see if it is in conf_get_devs.
 119     Warn if not.
 120   DONE, but don't warn yet...
 121
 122 * Support multipath ... maybe...
 123   maybe DONE
 124
 125 * --follow to syslog
 126
 127 * --follow to move spares around DONE
 128
 129 * --follow to notice other events: DONE
 130      rebuild started
 131      spare activated
 132      spare removed
 133      spare added
 134
 135 ------------------------------------
 136 - --examine --scan scans all drives and build an mdadm.conf file DONE
 137
 138 - check superblock checksum in examine DONE
 139 - report "chunk" or "rounding" depending on raid level DONE
 140 - report "linear" instead of "-1" for raid level DONE
 141 - decode ayout depending on raid level DONE
 142 - --verbose and --force flags. DONE
 143
 144 - set md_minor, *_disks for Create  - DONE
 145 - for create raid5, how to choose between
 146    all working, but not insync
 147    one missing, one spare, insync  DONE (--force)
 148 - and for raid1 - some failed drives...  (missing)
 149
 150 - when RUN_ARRAY, make sure *_disks counts are right
 151
 152 - get --detail to extract extra stuff from superblock,
 153    like uuid  DONE
 154 - --detail --brief to give a config file line DONE
 155 - parse config file. DONE
 156 - test...
 157
 158 - when --assemble --scan, if an underlying device is an md device,
 159   then try to assemble that device first.
 160
 161
 162 - mdadm -S /dev/md0 /dev/md1 gives internal error FIXED
 163
 164 - mdadm --detail --scan print summary of what it can find? DONE
 165
 166
 167 ---------
 168 Assemble doesn't add spares. - DONE
 169 Create to allow "missing" name for devices.
 170 Create to accept "--force" for do exactly what is requested
 171 - get Assemble to upgrade devices if force flag.
 172 ARRAY lines in config file to have super_minor=n
 173 ARRAY lines in config file to have device=pattern, and only accept
 174    those devices
 175    If UUID given, insist on that
 176    If not, but super_minor given, require all found with that minor
 177     to have same uuid
 178    If only device given, all valid supers on those devices must have
 179     same uuid
 180 allow /dev/mdX as first argument before any options
 181 Possible --dry-run option for create and assemble--force
 182
 183 Assemble to check that all devices mentioned in superblock
 184   are present.
 185
 186 New mode: --Monitor (or --Follow)
 187   Periodically check status of all arrays (listed in config file).
 188   Log every event and apparent cause - or differences
 189   Email and alert - or run a program - for important events
 190   Move spares around if necessary.
 191
 192   An Array line can have a spare-group= field that indicates that
 193    the array shares spares with other arrays with the same
 194    spare-group name.
 195    If an array has a failed and no spares, then check all other
 196      arrays in the spare group.  If one has no failures and a spare,
 197      then consider that spare.
 198     Choose the smallest considered spare that is large enough.
 199     If there is one, then hot-remove it from it's home, and
 200     hot-add it to the array in question.
 201
 202   --mail-to address
 203   --alert-handler program
 204
 205   Will also extract information from /proc/mdstat if present,
 206   and consider 20% marks in rebuild as events.
 207
 208   Events are:
 209      drive fails  - causes mail to be sent
 210      rebuild started
 211      spare activated
 212      spare removed
 213      spare added