2015-12-14 0:56 GMT+01:00 Phil Turmel [off-list ref]:

On 12/13/2015 06:50 PM, Phil Turmel wrote:

quoted

On 12/13/2015 01:18 AM, TheGerwazy . wrote:

quoted

Hello
I have to recreate mdadm raid 6 made with different data offsets. Some
drives have 2048 and others 262144.
I am looking for mdadm version with data offsets option for each drive.
Could somebody help me. Please ?

version 3.3 and above, I believe.  If in doubt, just compile the latest
version yourself -- no root privileges are required to compile it.  Then
run it from the current directory.

git clone git://neil.brown.name/mdadm

make
[sudo] ./mdadm ......

I should add that using --create to reconstruct an array is incredibly
dangerous (to your data) and should only be used as a last resort and
when you are 100% confident you know how to do it.  Your question
suggests that might not be true....  in which case sharing your problem
here might be wise.

Phil

Hi  Phil
Thanks for the message .... but,
In the last version of mdadm I get:

./mdadm --create --raid-devices=8 --level=6 --assume-clean /dev/md7
/dev/mapper/ovsdb1:1024 /dev/mapper/ovsdc1:4096
/dev/mapper/ovsdd1:1024 /dev/mapper/ovsde1:1024
/dev/mapper/ovsdf1:1024 /dev/mapper/ovsdg1:1024
/dev/mapper/ovsdh1:1024 /dev/mapper/ovsdi1:4096
mdadm: cannot open /dev/mapper/ovsdb1:1024: No such file or directory

but, There is branch data_offset of mdadm 3.2.5:

sudo ./mdadm --create --raid-devices=8 --level=6 --assume-clean
/dev/md7 /dev/mapper/ovsdb1 /dev/mapper/ovsdc1:4096
/dev/mapper/ovsdd1:1024 /dev/mapper/ovsde1:1024
/dev/mapper/ovsdf1:1024 /dev/mapper/ovsdg1:1024
/dev/mapper/ovsdh1:1024 /dev/mapper/ovsdi1:4096

dadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md7 started.

so it is exactly what I need :)

BTW is it possible to find right data offset without superblock on drive ?

Regards, Gerard