6 Reasons to Use 16GB of RAM for a ZFS NAS

16GB is the sweet spot for a home NAS running TrueNAS with ZFS. 8GB works for basic file serving, but you will notice the difference in anything beyond that.

ZFS uses ARC (Adaptive Replacement Cache) to keep frequently accessed data in memory. More RAM means more caching and snappier transfers.

With 8GB, the ARC gets choked, forcing the system to access disks more often. This kills performance, especially with multiple users or apps like Plex or Nextcloud.

ZFS is notoriously bad at recovering from low-memory situations. If you run out of RAM, things get weird.

16GB gives you breathing room. It is not much more expensive, and future-you will thank you.

Skip 8GB unless your NAS is purely a backup target that nobody touches. Otherwise, 16GB is the floor.