What to do when Ubuntu Device-mapper seems to be invincible!

I’ve been trying a dozen different configurations of my 2x500GB SATA drives over the past few days involving switching between ACHI/IDE/RAID in my bios (This was after trying different things to solve my problems with Ubuntu Lucid Lynx) ; After each attempt I’ve reset the bios option, booted into a live CD, deleting partitions and rewriting partition tables left on the drives.

Now, however, I’ve been sitting with a /dev/mapper/nvidia_XXXXXXX1 that seems to be impossible to kill!

It’s the only ‘partition’ that I see in the Ubuntu install (but I can see the others in parted) but it is only the size of one of the drives, and I know I did not set any RAID levels other than RAID0.

Thanks to wazoox for eliminating a possibility involving LVM issues with lvremove and vgremove, but I found what works for me.

After a bit of experimenting, I tried

<code>$dmraid -r
</code>

so see what raid sets were set up, then did

<code>$dmraid -x
</code>

but was presented with

ERROR: Raid set deletion is not supported in “nvidia” format

Googled this and found this forum post that told me to do this;

<code>$dmraid -rE
</code>

And that went through, rebooted, hoped, waited (well, while i was waiting, set the bios back to AHCI), and repartitioned, and all of (this particular issue) was well again. Hope this helps someone else down the line!

(This is a duplicate of my ServerFault query on this that I answered myself)