Re: RAID 5 inaccessible - continued

[Krekna Mektek <krekna@gmail.com>]

Er,,, no :)
This was on another machine, luckily, I am not that stupid.
I was using /dev/hdb in that one, sorry to be a bit unclear about that.
Also, I usually sit on my hands for a sec when I do such powerfull commands.

Good, so I make some chances then with dd_rescue, I'll let you know
then, I have to try this tonight.

Krekna


2006/2/15, Burkhard Carstens <suse-ml@onlinehome.de>:
> Am Dienstag, 14. Februar 2006 11:35 schrieb Krekna Mektek:
> [...]
> > Actually, /dev/hdd1 partition is 390708801 blocks, the disk itself is
> > a Hitachi 400GB disk.
> > So this is 390708801 blocks of 1024 bytes. This is according to my
> > calculation 400085812224 bytes.
> > The Faulty-RAIDDisk.img is according to my ls -l 400085771264 bytes.
> >
> > So it looks like they are quite the same, and the difference between
> > the two is 40960 bytes. These are 40 blocks, so 36 are missing?
> >
> > The dd actually succeeded, and did finish the job in about one day.
> > The badblocks were found after about the first 7 Gigs.
> >
> > Is there no way like the conv=noerror for mdadm, to just continue?
> > Can I restore the superblock on the .img file somehow?
> > Is it probably save to --zero-superblock all the three disks and that
> > the RAID array will create two new superblocks (Leaving the spare
> > out, because its probably out of date).
> >
> > I can do the dd again, but I think it will do the same thing, because
> > it finished 'succesfully'.
> > The superblock is at the end of the disk I read, about the last
> > 64-128K or something.
>
> My experience is that dd conv=noerror doesn't do the job correctly!! It
> still won't write a block that it cannot read.
> Please use "dd_rescue -A /dev/hdd1 /mnt/hdb1/Faulty-RAIDDisk.img"
> instead. See "dd_rescue --help".
>
> > ADEVICE /dev/hdb1 /dev/hdc1 /dev/loop0
> > ARRAY /dev/md0 devices=/dev/hdb1,/dev/hdc1,/dev/loop0
>
> another thing: /mnt/hdb1/ is not the same hdb1, you are using in the
> raid5, is it?
>
> It might be a bad idea to mount /dev/hdb1, write to it,
> and afterwards assemble the array with hdb1 being part of it ... Extra
> bad, if loop0 points to a file on hdb1 ?? However, if you did dd to a
> file on the partition, that should be part of the degraded raid5 array,
> I guess your data is already gone ...
>
> Good luck
>  Burkhard
>
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