Op 30-11-20 om 21:51 schreef antlists:

On 30/11/2020 20:05, David T-G wrote:

quoted

You don't see any "filesystem" or, more correctly, partition in your

   fdisk -l

output because you have apparently created your filesystem on the entire
device (hey, I didn't know one could do that!). 

That, actually, is the norm. It is NOT normal to partition a raid array.

It's also not usual (which the OP has done) to create a raid array on
top of raw devices rather than partitions - although this is down to
the fact that various *other* utilities seem to assume that an
unpartitioned device is free space that can be trampled on. Every now
and then people seem to lose their arrays because an MBR or GPT has
mysteriously appeared on the disk.

And as long as you take care that the mdadm.conf in the initrd is
correct and reflects the true status, all should be well.

If this is not the case, you almost certainly get initrd barfing at you,
if not at first boot in that condition, than once an error has occurred.

Cheers

Rudy

P.S. doing a raid as the OP has done is not what the debian installer
will do.