Nagy Zoltan wrote:
hi all,
i've set up a two dimensional array:
* leaf nodes composes raid5 arrays from their disks, and export it as
a iSCSI target
* the root node creates a raid5 on top of the exported targets
in this setup i will have to face that an array component can(and would)
grow, so i
created a test case for this to see what comes out ;)
* after growing the components mdadm won't recognized them anymore as
an array member
(because there are no superblock at the end of the device - last
64k?)
i've tried to inform mdadm about the size of the components, but
it sad no ;)
* i've added an arbitary superblock copy operation after the
expansion, to make possible for
mdadm to recognize and assemble the array - it's working, and passes
my test.
is there a less 'funky' solution for this ;)
can i run into any trouble when doing this on the real system?
I would simply use a v1.1 superblock which will be situated at the start of
the array. Then you will face another problem - once you grow a leaf device,
mdadm will not see the new size as it will find the superblock at sect 0 and
will be done there. You will need to issue mdadm -A ... --update devicesize.
The rest of the operations are identical.
As a side note I am also curious why do you go the raid55 path (I am not very
impressed however :)
Peter
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