[hestefisk]

That’s likely because Synology doesn’t offer ZFS or anything near the same capabilities.

[black3r]

synology uses btrfs which provides almost the same capabilities, but ZFS usually eats all the RAM it gets as some sort of cache to speed up disk operations.

[hestefisk]

You are thinking of the ARC. By default, ZFS will allocate what is available but you can constrain it as you like.