> deduplicating filesystems (BRTFS, ZFS) can reduce your memory and storage requirements

This is getting into a pretty tangential discussion, but I'd be surprised if there are net memory savings from deduplication. Disk yes, but the dedup process itself has significant memory overhead (both in memory usage, and memory accesses), which would need to be offset to have a net win. At least on ZFS, it's usually recommended to turn it on only for large-RAM servers where the saving in disk space (and/or reduction in uncached disk access) is worth allocating the memory to it.