I moved from FreeNAS to Unraid. They both have their pros and cons, that's for another thread. Anyways FreeNAS uses the system RAM for its cache, so pretty much the more RAM the better for FreeNAS so I put lots of RAM in it. In Unraid the RAM is pretty much usless its sits at 1% utilized and i think thats the minimum that the dashboard can display, I think once I've seen 2% used. It would be nice if Unraid could use RAM as a cache drive or a second cache for file transfers and/or docker/VMs. I would prefer to have my dockers on nonvolatile cache, but could write this cache to disk apon restart or shutdown like FreeNAS does. I'm sure I'm in a minority for this feature do to the potential data loss risk. The mover can be scheduled to run hourly I would be willing to risk it for an hour or two for the high speed transfer rate I would get using RAM on a 10GBe connection. Thank you for your time.

FreeNAS (ZFS) uses most available RAM for read cache (ARC), write cache functions similarly to Unraid, it uses about 1/8 total RAM, Unraid uses 20% free RAM, both flush any data thee after a few seconds.