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       mdadm is a tool for  creating,  managing,  and  monitoring
       RAID devices using the md driver in Linux.

       Some  common  tasks, such as assembling all arrays, can be
       simplified by describing the devices and  arrays  in  this
       configuration file.

       The file should be seen as a collection of words separated
       by white space (space, tab, or newline).   Any  word  that
       beings with a hash sign (#) starts a comment and that word
       together with the remainder of the line is ignored.

       Any line that starts with white space (space  or  tab)  is
       treated  as  though it were a continuation of the previous

       Empty lines are ignored, but otherwise each (non continua­
       tion) line must start with a keyword as listed below.  The
       keywords are case insensitive and can be abbreviated to  3

       The keywords are:

       DEVICE A  device  line lists the devices (whole devices or
              partitions) that might contain a component of an MD
              array.   When  looking  for  the  components  of an
              array,  mdadm  will  scan  these  devices  (or  any
              devices listed on the command line).

              The  device  line may contain a number of different
              devices (separated by spaces) and each device  name
              can contain wild cards as defined by glob(7).

              Also,  there may be several device lines present in
              the file.

              Alternatively, a device line can contain  the  word
              partitions.    This   will   cause  mdadm  to  read
              /proc/partitions and include all devices and parti­
              tions found there-in.  mdadm does not use the names
              from /proc/partitions but only the major and  minor
              device  numbers.   It  scans  /dev to find the name
              that matches the numbers.

              For example:
              Each  identity word has a tag, and equals sign, and
              some value.  The tags are:

           uuid=  The value should be a 128 bit uuid in hexadeci­
                  mal,  with punctuation interspersed if desired.
                  This  must  match  the  uuid  stored   in   the

                  The  value  is  an  integer which indicates the
                  minor number that was stored in the  superblock
                  when  the  array  was created. When an array is
                  created as /dev/mdX, then the minor number X is

                  The  value  is a comma separated list of device
                  names or device name  patterns.   Only  devices
                  with  names  which  match one entry in the list
                  will be used to assemble the array.  Note  that
                  the devices listed there must also be listed on
                  a DEVICE line.

           level= The value is a raid level.  This  is  not  nor­
                  mally  used  to  identify an array, but is sup­
                  ported so that the output of

                  mdadm --examine --scan

                  can be use directly in the configuration  file.

                  The  value  is  the number of devices in a com­
                  plete active array.  As  with  level=  this  is
                  mainly for compatibility with the output of

                  mdadm --examine --scan.

                  The  value  is  a  textual  name for a group of
                  arrays.  All arrays with the  same  spare-group
                  name  are  considered  to  be  part of the same
                  group.  The significance of a group  of  arrays
                  is that mdadm will, when monitoring the arrays,
                  move a spare drive from one array in a group to
                  another  array in that group if the first array
                  had a failed or missing drive but no spare.

              possibly the related component device.

              There should only be one program line and it should
              be give only one program.


       DEVICE /dev/sd[bcdjkl]1
       DEVICE /dev/hda1 /dev/hdb1

       # /dev/md0 is known by it's UID.
       ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
       # /dev/md1 contains all devices with a minor number of
       #   1 in the superblock.
       ARRAY /dev/md1 superminor=1
       # /dev/md2 is made from precisey these two devices
       ARRAY /dev/md2 devices=/dev/hda1,/dev/hda2

       # /dev/md4 and /dev/md5 are a spare-group and spares
       #  can be moved between them
       ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
       ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977

       MAILADDR root@mydomain.tld
       PROGRAM /usr/sbin/handle-mdadm-events


       mdadm(8), md(4).


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