On Sat, Nov 30, 2019 at 10:02 AM Andrei Borzenkov <arvidjaar@xxxxxxxxx> wrote: > > GRUB is normally using hints - grub-install (and grub-mkconfig) tries to > guess firmware device name. At boot time grub tries to access hinted > device first, if it succeeds, it does not try anything else. With second > btrfs partition grub needs to find second device at boot time so it now > probes everything and hits those vendor media devices. > > At least this explains what you see as well as ... > > > Last time this > > happened, all I did was remove the 2nd device and the problem went > > away. > > ... this. Ahhh, that makes complete sense. So it is Btrfs multiple device related, but not a bug in btrfs.c per se. > > If you go in grub shell in this state (without errors), do you see those > ghost devices? Uncertain. My vague memory recall is that yes they are there, because I found their existence strange and different compared to pre-GRUB 2.02 where on this same system I'd see only either hd0 or hd1 (one without the other), along with cd0. But something changed either with a firmware update from Apple, or GRUB, that resulted in additional GRUB devices, hd2, hd3, hd4, hd5. > > I'm ready to try that again (remove the 2nd device) and see if > > the problem goes away, but has enough information been collected about > > the present state? > > > > > > If you are reasonably sure that all errors are related to those phantom > devices - I would say yes, the reason for these phantom devices to exist > is already clear. I'll give it a shot in a bit. -- Chris Murphy
