Using 2.6.31 liveCD to grow (reshape) raid5 into raid6, then bacck to old kernel?

[Janek Kozicki <janek_listy@wp.pl>]

Hi,

I have an old debian etch backup server. It has 5 drives in raid4.
I want to add a sixth drive to jump to raid6. I don't want to upgrade
debian etch, because the server is working real fine, and doing an
upgrade would be too much problems.

Here it is:

  backup:~# uname -a
  Linux backup 2.6.24-etchnhalf.1-686 #1 SMP Sat Aug 15 16:51:49 UTC 2009 i686 GNU/Linux

  backup:~# mdadm -D /dev/md1
/dev/md1:
        Version : 01.01.03
  Creation Time : Fri Nov  2 23:35:37 2007
     Raid Level : raid5
     Array Size : 1933614592 (1844.04 GiB 1980.02 GB)
    Device Size : 966807296 (461.01 GiB 495.01 GB)
   Raid Devices : 5
  Total Devices : 5
Preferred Minor : 1
    Persistence : Superblock is persistent

  Intent Bitmap : Internal

    Update Time : Thu Nov 12 21:59:15 2009
          State : active
 Active Devices : 5
Working Devices : 5
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 128K

           Name : backup:1  (local to host backup)
           UUID : 22f22c35:99613d52:31d407a6:55bdeb84
         Events : 718938

    Number   Major   Minor   RaidDevice State
       5      22        3        0      active sync   /dev/hdc3
       1       8        3        1      active sync   /dev/sda3
       3       3        3        2      active sync   /dev/hda3
       4       8       35        3      active sync   /dev/sdc3
       6       8       19        4      active sync   /dev/sdb3
backup:~# 


And so my plan is to get some liveCD with 2.6.31 (or maybe 2.6.32 ?).
Connect the sixth drive, boot liveCD, perform the migration:

mdadm --add /dev/md2 /dev/sdd3
mdadm --grow /dev/md2 --level=raid6 --raid-disks=6

Then reboot back into linux 2.6.24.

Will this work?

Will 2.6.24 understand such raid6 ?

thanks a lot for your help
-- 
Janek Kozicki                                                         |