Raid1 container

[Kolesar]

I have RAID 1 on my environment and I detect one issue in script:
rear/usr/share/rear/layout/save/GNU/Linux/210_raid_layout.sh

Output of mdadm is:

mdadm --misc --detail /dev/md127
/dev/md127:
        Version : imsm
     Raid Level : container
  Total Devices : 2

Working Devices : 2


           UUID : fe5173d0:dfb8783b:b19d7a81:c0715868
  Member Arrays : /dev/md/raid01

    Number   Major   Minor   RaidDevice

       0       8       16        -        /dev/sdb
       1       8        0        -        /dev/sda

As you can see, here we do not have Raid Devices in output and 210_raid_layout.sh break in line 44

rear/usr/share/rear/layout/save/GNU/Linux/210_raid_layout.sh

Line 44 in 2c12a52

let sparedevices=$totaldevices-$ndevices

because variable ndevices is empty.

Easy workaround is adding one if statement before line 44, like:

            if [ -z "$ndevices" ] ; then
                ndevices=0
            fi

But, I guess that command for Raid Level: container should be different.

Note: Command for another block device is OK

mdadm --misc --detail /dev/md126
/dev/md126:
      Container : /dev/md/imsm0, member 0
     Raid Level : raid1
     Array Size : 976759808 (931.51 GiB 1000.20 GB)
  Used Dev Size : 976759940 (931.51 GiB 1000.20 GB)
   Raid Devices : 2
  Total Devices : 2

          State : active 
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0


           UUID : 7e085b05:d8a58ee9:95b5187f:039d725c
    Number   Major   Minor   RaidDevice State
       1       8        0        0      active sync   /dev/sda
       0       8       16        1      active sync   /dev/sdb

[jsmeix]

@Kolesar
I have no personal experience with RAID setup
so that I cannot really help here.

In general for issues where you already have a fix
I suggest that you submit a GitHub pull request
with your proposed fix, cf.
http://relax-and-recover.org/development/
and see in particular
https://github.com/rear/rear/wiki/Coding-Style

That code in 210_raid_layout.sh was mainly made in 2011 via
8125ec3
at that time in 21_raid_layout.sh so that this code
might need some general adaptions to keep it up-to-date
plus enhancements for things like "Raid Level: container".

[jsmeix]

See also
#1540 (comment)

[jsmeix]

@Kolesar
I assume you also have the special Intel Matrix RAID hardware, cf.
#1540 (comment)

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