zfs

[root@test1 ~]# zdb arsiv -D
DDT-sha256-zap-duplicate: 2663735 entries, size 322 on disk, 179 in core
DDT-sha256-zap-unique: 1581858 entries, size 421 on disk, 322 in core

dedup = 4.57, compress = 1.63, copies = 1.00, dedup * compress / copies = 7.46