BlackHole 是一个无数据重复的网络块设备，支持镜像、快照以及多 LUNs 使用相同的存储。
It is filesystem agnostic and has been tested with ext2/3/4, NTFS, ReiserFS, and the Oracle Cluster File System (OCFS2). It supports encryption, compression, and multiple storage backends. The hashing scheme used is user configurable. The program exports an NBD device which can be mounted in Linux and GNU/Hurd.
