Simple. ZFS has memory requirements to operate efficiently. If you have less <8Gb of RAM, which is by the way as small as it gets, then you probably have not a

Simple. ZFS has memory requirements to operate efficiently. If you have less <8Gb of RAM, which is by the way as small as it gets, then you probably have not a lot of drives, therefore won't benefit from ZFS nor FreeNAS. Kind of like when you don't need a full blown CRM to manage two customers.