Re: Raid Array with 3.5Tb

On Thursday January 15, evan.felix@pnl.gov wrote:

I've been attempting to create a large raid 5 device using the linux
2.6.1 kernel, with the Large Block Device configured on.  I have in the
system 16 250G disks.  I built an array with mdadm -C -n 15 -x 1
/dev/md2 /dev/sd[a-p]

The resync/recovery seemed to be going fine, but at some point i started
seeing:

kernel: compute_blocknr: map not correct
kernel: compute_blocknr: map not correct

...

Has anyone else made an array this large? and does anybody have any
pointers on where i can start looking at code to fix this?

I would look in  drivers/md/raid5.c and compute_blocknr() in that file.

I would change "chunk_number" to a sector_t and change:
	chunk_number = stripe * data_disks + i;
to read
	chunk_number = (sector_t)stripe * data_disks + i;

Possibly "stripe" and "chunk_number" should both be "sector_t", but
I'm not at all sure.

Please let me know if it helps.

NeilBrown