Re: Restoring a raid0 for data rescue

[tyranastrasz@gmx.de]

Your numbers were correct, everything is perfect from you.
Yes it is everything on the 1800GB partition, ext4. It's consistency is
by 100%.
It worked perfectly!

You saved over 6 month of hard work!
Thank you so much!

The heatwave killed my braincells :/

All who helped get included of my godnight prayer, thank you :)

Nara
- Can now sleep well

On 03.08.20 06:37, NeilBrown wrote:
> On Sun, Aug 02 2020, tyranastrasz@gmx.de wrote:
>>
>> I tried something what was told here
>> https://askubuntu.com/questions/69086/mdadm-superblock-recovery
>>
>> root@Nibler:~# mdadm --create /dev/md0 -v -f -l 0 -c 128 -n 2 /dev/sdd
>> /dev/sdb
>
> That was a mistake.  I probably could have saved you before you did
> that.  Maybe I still can...
>
> You have an Intel IMSM RAID0 array over sdb and sdd.
> This was 3711741952 sectors in size using the first 1855871240 sectors
> of each device - data arranged in 7249496 256KiB stripes (128KiB on each
> device).
>
> This 1900GB array was partitioned into 3 partitions: 3MB, 1800MB,
> and 18MB.
>
> Presumably the data you want is on the 2nd partition: the 1800MB one?
>
> When you ran the "mdadm --create" command it wrote some meta data at the
> start of the device - probably only a 4K block at 8K from the start.
> This is before the first partition, so it might not have affected any
> data at all.  It may have corrupted the partition table.
>
> You need to put the array together again without writing anything to
> it.  Fortunately that is fairly easy with RAID0.
>
> 1/ If /dev/md0 still exists, stop it "mdadm --stop /dev/md0"
> 2/ put the two devices into a RAID0 with no metadata.
>      mdadm --build /dev/md0 -n 2 -z 927935620 -c 128 -l 0 /dev/sdb /dev/sdd
>
> 3/ create a read-only loop device over the second partition
>      losetup -r -o 4096K --sizelimit 7176980M /dev/loop0 /dev/md0
>
> 4/ Examine the filesystem at /dev/loop0 READ-ONLY.
>    You didn't say what sort of filesystem you used.  If ext4, then
>       fsck -n /dev/loop0
>
> 5/ If it looks good, try mounting /dev/loop0 READ-ONLY.
>
> I recommend that you FIRST read the relevant parts of the mdadm and
> losetup man pages, and check my arithmetic to make sure the numbers that
> I have given are correct.  If unsure, ask.
>
> If it doesn't work, I recommend reporting results, asking, and waiting
> before doing anything that might change anything on the drives.
>
> NeilBrown
>