This blog by user Nahraf details his journey of moving from FreeNAS to FreeBSD to better accommodate his use cases. Check out the blog to see his detailed instructions for the zpool transitioning.

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I love FreeNAS. Its awesome, well built, well-supported. But as my needs increased, I wanted to use my FreeNAS box for more than the basics. In particular, I was moving towards a single host to run as a:

  1. Family NAS server
  2. Development server
  3. IRC client
  4. VM server
  5. Web server
  6. Email Server
  7. Git Server
  8. Home Firewall
  9. Home IPv6 gateway
  10. IPv6 VPN and Jump box

FreeNAS could easily do all of this. But I found myself using the device for everything but a NAS server. Also, as my experience on FreeBSD reaching proficient-status, I wanted to jump in the deep end and manually configure a production system from scratch. So I thanked FreeNAS for their contribution, yanked out the USB disks and installed FreeBSD 11.1 on a separate USB disk.

Original post:

Migrating from FreeNAS to FreeBSD