As a workaround, I installed the 5.4 kernel using mainline and my raid1 btrfs volume seems to be mounting fine..The issue is present even with latest mainline 5.13 kernel..so definitely more people should be seeing this.. as and when probably they create/convert to raid 1..
@:~$ uname -a Linux monster 5.4.126-0504126-generic #202106160800 SMP Wed Jun 16 12:12:41 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux @:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 21.04 Release: 21.04 Codename: hirsute @:~$ mount | grep btrfs /dev/sdd1 on /mnt/datanew type btrfs (rw,relatime,space_cache,subvolid=5,subvol=/) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1931790 Title: Unable to mount btrfs RAID 1 filesystem after reboot - Error - device total_bytes should be at most X but found Y To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1931790/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs