Intermittent mount issues
This issue could be specific to loop devices only.
# mount -t btrfs /dev/loop1 /var/lib/lxc
mount: wrong fs type, bad option, bad superblock on /dev/loop1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
[ 622.758555] btrfs: failed to read the system array on loop1
[ 622.761205] btrfs: open_ctree failed
mount using another device in the storage pool
mount -t btrfs /dev/loop2 /var/lib/lxc
Use btrfs for LXC (Linux Containers) backing store
LXC works very well with Btrfs, it makes use of Btrfs snapshot feature to clone containers. When using lxc-create, the -B need NOT to be specified as it will be used automatically if the /var/lib/lxc filesystem is found to be Btrfs.
'backingstore' is one of 'none', 'lvm', or 'btrfs'. The default
is 'none', meaning that the container root filesystem will be a
directory under /var/lib/lxc/container/rootfs. The option
'btrfs' need not be specified as it will be used automatically
if the /var/lib/lxc filesystem is found to be btrfs. If back?
ingstore is 'lvm', then an lvm block device will be used and the
following further options are available: --lvname lvname1 will
create an LV named lvname1 rather than the default, which is the
container name. --vgname vgname1 will create the LV in volume
group vgname1 rather than the default, lxc. --fstype FSTYPE
will create an FSTYPE filesystem on the LV, rather than the
default, which is ext4. --fssize SIZE will create a LV (and
filesystem) of size SIZE rather than the default, which is 1G.