Re: RAIDframe changes its unit number

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Wed, 30 Sep 2015 09:07:32 -0600
    From:        Greg Oster <oster%netbsd.org@localhost>
    Message-ID:  <20150930090732.143716a7%mickey.usask.ca@localhost>

  | I agree that it'd be nice to have an IOCTL for raidctl to change which
  | device a RAID set will show up as on next reboot... It's not that hard
  | to do -- just requires time to do a little coding.  

There would be occasional uses for something like that, but really, as
long as it remains stable, it makes no difference at all what the raid
unit numbers are (one of my systems has raid1 raid2 raid4 and raid7 active
on it, and no raid0 raid3 raid5 or raid6).

What would be more useful, if development cycles could be found, would be
better protection from getting into this situation in the first place.
This isn't the first time people have caused trouble for themselves by
plugging in drives with (old) raidframe filesystems on them.

In this case, rather than finding two different raid0's, and "fixing"
things by changing one of them (in this case, unfortunately it seems,
the "wrong" one) to raid1, a better solution would have been to just
blather on the console about the problem, and refuse to configure either
of them (since raidframe has no way to know which one really should be
there - two different autoconfigured raid0's always indicates some
problem somewhere though).

in this case, most likely, the boot would simply have failed (I'm guessing)
and the added drive with the irrelevant raid0 on it would just have been
removed again, and all would have reverted to normal - after clearing the
raid info from it, the drive could have been safely inserted.

kre