Controls number of copies stored of each block, above and beyond any redundancy of the storage
pool. Metadata is always stored with multiple copies, but this property allows the same behavior to
be applied to data blocks. The storage pool attempts to store these extra blocks on different
devices, but it is not guaranteed. In addition, a storage pool cannot be imported if a complete
logical device (RAID stripe, mirrored pair, etc) is lost. This property is not a replacement for
proper replication in the storage pool, but can be reassuring for paranoid administrators.
Normal (Single Copy)
Default behavior. Store a single copy of data blocks.