mdadm/TODO

?? Allow -S /dev/md? - current complains subsequent not a/d/r - DONE

* new "Query" mode to subsume --detail and --examine.
   --query or -Q, takes a device and tells if it is an MD device,
   and also tells in a raid superblock is found. 
 DONE

* write mdstat.c to parse /proc/mdstat file
   Build list of arrays:  name, rebuild-percent
  DONE

* parse /proc/partitions and map major/minor into /dev/* names,
  and use that for default DEVICE list ????

* --detail --scan to read /proc/mdstat, and then iterate over these,
    but assume --brief.  --verbose can override
    check each subdevice to see if it is in conf_get_devs.
    Warn if not.
  DONE, but don't warn yet...

* Support multipath ... maybe...
  maybe DONE

* --follow to syslog 

* --follow to move spares around

* --follow to notice other events:
     rebuild started
     spare activated
     spare removed
     spare added

------------------------------------
- --examine --scan scans all drives and build an mdadm.conf file DONE

- check superblock checksum in examine DONE
- report "chunk" or "rounding" depending on raid level DONE
- report "linear" instead of "-1" for raid level DONE
- decode ayout depending on raid level DONE
- --verbose and --force flags. DONE

- set md_minor, *_disks for Create  - DONE
- for create raid5, how to choose between 
   all working, but not insync
   one missing, one spare, insync  DONE (--force)
- and for raid1 - some failed drives...  (missing)

- when RUN_ARRAY, make sure *_disks counts are right

- get --detail to extract extra stuff from superblock,
   like uuid  DONE
- --detail --brief to give a config file line DONE
- parse config file. DONE
- test...

- when --assemble --scan, if an underlying device is an md device, 
  then try to assemble that device first.


- mdadm -S /dev/md0 /dev/md1 gives internal error FIXED

- mdadm --detail --scan print summary of what it can find?


---------
Assemble doesn't add spares. - DONE
Create to allow "missing" name for devices.
Create to accept "--force" for do exactly what is requested
- get Assemble to upgrade devices if force flag.
ARRAY lines in config file to have super_minor=n
ARRAY lines in config file to have device=pattern, and only accept
   those devices
   If UUID given, insist on that
   If not, but super_minor given, require all found with that minor
    to have same uuid
   If only device given, all valid supers on those devices must have 
    same uuid
allow /dev/mdX as first argument before any options
Possible --dry-run option for create and assemble--force

Assemble to check that all devices mentioned in superblock
  are present.

New mode: --Monitor (or --Follow)
  Periodically check status of all arrays (listed in config file).
  Log every event and apparent cause - or differences
  Email and alert - or run a program - for important events
  Move spares around if necessary.

  An Array line can have a spare-group= field that indicates that
   the array shares spares with other arrays with the same
   spare-group name.
   If an array has a failed and no spares, then check all other
     arrays in the spare group.  If one has no failures and a spare,
     then consider that spare.
    Choose the smallest considered spare that is large enough.
    If there is one, then hot-remove it from it's home, and
    hot-add it to the array in question.

  --mail-to address  
  --alert-handler program
  
  Will also extract information from /proc/mdstat if present,
  and consider 20% marks in rebuild as events.

  Events are:
     drive fails  - causes mail to be sent
     rebuild started
     spare activated
     spare removed
     spare added