Re: add fails: nvme1n1p2 does not have a valid v1.2 superblock, not importing

[Roman Mamedov <rm@romanrm.net>]

On Tue, 6 May 2025 12:25:13 +0200
Daniel Buschke <damage@devloop.de> wrote:

> 1. What exactly does this error message mean? I think replacing a failed 
> drive with a new one is what RAID is for? So this shouldn't be an issue 
> at all?
> 
> 2. During my search I got the feeling that the problem is that the 
> failed drive is somehow still "present" in the raid. Thus the add is 
> handled as a "re add" which fails because there is no md superblock on 
> the new device. Is my conclusion correct?
> 
> 3. If 2. is correct how do I remove the failed but not really present 
> device? Commands like "mdadm ... --remove failed" did not help.
> 
> 4. I already replaced old devices in this RAID successfully before. What 
> may have changed that this issue happens?

I agree that it is a weird error to get in this situation. "man mdadm" gives
something to try:

       --add-spare
              Add  a  device as a spare.  This is similar to --add except that
              it does not attempt --re-add first.  The device will be added as
              a  spare  even  if it looks like it could be an recent member of
              the array.

Another idea (from the same man page) would be "mdadm ... --fail detached".

-- 
With respect,
Roman