How to manage storage volumes - LXD documentation (linuxcontainers.org)
By default, the custom storage volume is added to the instance with the volume name as the [device] name. If you want to use a different device name, you can add it to the command:
lxc storage volume attach <pool_name> <block_volume_name> <instance_name> <device_name>
lxc storage volume attach pl block2 jam2 vd1
Error: Failed add validation for device “block2”: Custom block volumes cannot have a path defined