RAM required for ZFS?

  • Some of the smaller hardware options (like APU boards) have either 2GB or 4GB RAM.  They can take an SSD, but the RAM is fixed.  Will that be enough to use ZFS in addition to all the other firewall duties?

  • Rebel Alliance Developer Netgate

    It depends on what else you're doing with the firewall.

    IIRC we've decided, at least internally, not to recommend ZFS for anything with less than 4GB of RAM.

    That said, I have it running in a test VM with 512MB RAM using ZFS and though it's nearly using all of its memory (+some swap) it still manages to run a few small packages and VPNs.

    So can it work with less? Yes. Will it always work with less? Maybe not.

  • Even 1GB will work with some manual tuning, 2GBs will likely work out of the box without manual tuning. Since only amd64 is supported on pfSense when ZFS is used and the base for pfSense 2.4 is FreeBSD 11, most of the discussion in the article linked below doesn't apply except for the maximum size of the ARC cache. That should be tuned manually if you have less than 2GBs of memory and even with 2GBs you might want to do it to allow more memory for other kernel functions and running services.


  • I ordered an APU2 board with 4GB RAM so I should be good.  Thanks everyone.

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