Hello,
i am working on implementation of MD RAID1 and i am bit lost regarding
superblock 1.2 format. Can you please help with following?
I've created RAID1 like this:
DEVICE_COUNT = 1
DEVICE_NUMBER = 0
ROLES: 0x0000
mdadm reports it to be correct, used mdadm to grow it like this:
mdadm --grow /dev/md23 --raid-disks=2 --force
maddm /dev/md23 --add /dev/sdb1
Now i've inspected superblocks of both devices and i have following:
DEVICE_COUNT = 2
DEVICE_NUMBER = 0
ROLES: 0x0000 0xFFFF 0x0100
DEVICE_COUNT = 1
DEVICE_NUMBER = 2
ROLES: 0x0000 0xFFFF 0x0100
First device number is 0, why second device is 2 (while 1 being
skipped)? Should the count start at 1?
Why are there 3 roles now, when DEVICE_COUNT is 2 ? If count starts at
1, why would there be roles[0]?
I am bit confused. Obviously i am making some trivial mistake and i
don't want to keep guessing anymore.
Can you please tell me how to correctly handle this?
Thank you
Happy holidays!
--
S pozdravem
Best regards
Tomáš Mudruňka
