btrfs receive has some limitations for sure. I don't think having the volume mounted is a problem, but during the transfer the snapshot is read/write. If you mo

btrfs receive has some limitations for sure. I don't think having the volume mounted is a problem, but during the transfer the snapshot is read/write. If you modify the volume, subsequent differential updates will fail. If you have some other process messing with the snapshot being received, you also risk messing up the send/receive. There are also limitations w.r.t. the way the volume is mounted; if you alter the default mount point or mounted a subvolume somewhere deep in the chain, receive will also fail. If you have a BTRFS volume on a server that exists purely to receive backups and separate the subvolumes sufficiently (i.e. using specific subvolumes for the different backed up devices), I don't think send/receive should be a problem. I wouldn't back up to the root partition of a running system, I think a dedicated data volume makes a lot more sense design-wise.