Comment 5 for bug 880645

According to #btrfs on freenode, this problem occurs because balancing the filesystem raid1 mirrors the meta data. Then you are not allowed to remove any devices because the metadata wouldn't be raid1 mirrored any more. The weird question that comes from this is why are you allowed to make a btrfs filesystem with raid1 that only has one device in the first place?

It seems like you can not have the raid1 problem by making your btrfs partitions with 'mkfs.btrfs -m single -d single /dev/sdxx' which specifies that both the data (-d) and the metadata (-m) are not raid1 mirrored.