How much RAM do I need for a home NAS running ZFS?

16GB is the sweet spot for a home NAS running TrueNAS with ZFS. 8GB will work for basic file serving, but you’ll notice the difference with multiple users or apps like Plex or Nextcloud because ZFS uses ARC to cache data in RAM. More RAM means snappier transfers, and 16GB gives you breathing room to avoid performance issues and low-memory recovery problems. Skip 8GB unless your NAS is a purely backup target.