There are filesystems that support inline or post-process deduplication. btrfs[1] and zfs[2] come to mind as free ones, but there are also commercial ones like WAFL etc.
It's always a tradeoff. Deduplication is a CPU-heavy process, and if it's done inline, it is also memory-heavy, so you're basically trading CPU and memory for storage space. It heavily depends on the use-case (and the particular FS / deduplication implementation) whether it's worth it or not
Deduplication is included with every version and edition of windows server since 2012.
You need to license windows server properly of course, but there is no add-on cost for deduplication.
It's always a tradeoff. Deduplication is a CPU-heavy process, and if it's done inline, it is also memory-heavy, so you're basically trading CPU and memory for storage space. It heavily depends on the use-case (and the particular FS / deduplication implementation) whether it's worth it or not
[1]: https://btrfs.wiki.kernel.org/index.php/Deduplication
[2]: https://docs.oracle.com/cd/E36784_01/html/E39134/fsdedup-1.h...