He guys,
picking up this old topic cause i'm running into a similar problem. Running a Ubuntu 16.04 (HWE K4.8) server with 2 nvme SSD as Raid1 as /. Since one nvme died i had to replace it, where the trouble began. I replaced the nvme, bootet degraded, added the new disk to the raid (btrfs dev add) and removed the missing/dead device (btrfs dev del). Everything worked well. BUT as i rebooted i ran into the "BTRFS RAID 1 not mountable: open_ctree failed, unable to find block group for 0" because of a MISSING disk?! I checked the btrfs list and found that there was a patch that enabled a more strict behavior in handing missing devices (atm cant find the related patch anymore), which was merged some kernels before k4.8 but was NOT in k4.4. So i managed to install the k4.4 ubuntu kernel and the system startet booting and working again. So my pitty is that i cant update to anything after k4.4 with this production machine. :-( So 1st should be investigating why did the disk not get removed correctly? Btrfs dev del should remove the device corretly, right? Is there a bug? 2nd Was the restriction on handling missing devices to strikt? Is there a bug? 3rd i saw https://patchwork.kernel.org/patch/9419189/ from Roman. Did he receive any comments on his patch? This one could help on this problem, too. Regards Sash -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
