[Wylug-help] Help needed with 'failed' Linux software RAID 10

[John Hodrien]

On Sat, 29 May 2010, Dave Fisher wrote:

> Some years ago I made the mistake of putting my main home directory on
> a LVM2 over RAID 10.
>
> It's been a pain in the backside from the very start, made worse by my
> ignorance of both technologies and by the fact that never worked out a
> proper backup strategy ... despite several false starts.

LVM over MD is a nice place to be.  When you're done being baffled by that,
add iSCSI in on top, and be truly confused.

> Now I've run into what (at first sight) looks like my second
> near-death experience with the RAID array ... and just like last time,
> I mistakenly deleted both backups a couple of days ago.

> mdadm -A -s tells me that my array cannot be assembled from only one
> of the four partitions in the array.

Just in terms of making sure you know what's going on before anything else.

mdadm --misc --examine /dev/sd{a,b,c,d}{1,2,3}

Replacing said letters and numbers with the appropriate ones for your setup.

jh