Comment 2 for bug 125471

Scott James Remnant <email address hidden> writes:

>> Reported as https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/125471
>>
> This is not a regression though, right? We found nothing that made an
> attempt to force a degraded array to be used at boot.

No, I'd expect it to be triaged as wishlist bug for enhancment of the
package. I can imagine that espc. the ubuntu server people would be
interested in solving it.

> What suggestion would you make for it?

Basically the solution you suggested: Detect root on a degraded array,
and drop to busybox with a short explanation how to boot in degraded
mode.

> Note that removing --no-degraded doesn't work, since that's required to
> actually assemble the array. Without it, it would be always assembled
> degraded since block devices don't turn up at once. We'd need to
> examine the array status to see whether all components have been
> detected, and some marked as discarded.

Okay, so the detection would have to use some timeout value for
assembling the raid after finding/detecting the first drive.

> This won't work if a drive is removed; we can't tell the difference
> between that and a drive just hasn't been inserted or detected yet.

It seems to me that this should be configurable then. The default could
be to abort booting if the array is not complete with instructions how
to boot in degraded mode, and add documentation to the ubuntu-server
guide how to make the server boot without interaction in degraded mode
if a disk is missing.

The local admin would want to be notified (by email or other means)
about this incident, then.

--
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4