Re: Two Drive Failure on RAID-5

[Cry <cry_regarder@yahoo.com>]

Janos Haar <janos.haar <at> netcenter.hu> writes:

> Cry i only have this idea:
> dd_rescue -v -m 128k -r /dev/source -S 128k superblock.bin
> losetup /dev/loop0 superblock.bin
> mdadm --build -l linear --raid-devices=2 /dev/md1 /dev/sdg1 /dev/loop0

Janos,

The correct information should already be in /dev/sdg1 since I copied the entire
/dev/sda there (probably overwrote stuff in /dev/sdg2 since /dev/sda was 160K
bigger than /dev/sdg1).

This means I the superblock should already be there at the start of /dev/sdg1.
so the steps above should result in two superblocks being stacked back to back?

should I use an losetup offset into /dev/sdg1 to get to the real data and bypass
the MBR copied in from /dev/sda?  I am a bit confuse don how these things are
laid out.

Where on the disk does the information printed from mdadm -E /dev/sda and mdadm
-E /dev/sdg1 come from?

Thanks!

Cry