Checking the underlying mdraid with echo check > /sys/block/md0/md/sync_action
now has finished and it is just fine: cat /proc/mdstat Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sda3[0] sdb3[1] 2929833792 blocks super 1.2 [2/2] [UU] -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1559723 Title: soft lockup during btrfs balance To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1559723/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs