Minimal zfs (TrueNAS?) system for backups

[gth871r]

I have a Freenas (soon to be upgraded to TrueNAS Core) system that I'd like to have a local frequent backup of. After spending half a day futzing with a mediocre Qnap trying to get Rsync to work over SSH I've concluded that's not a great option.

It would be great if I could just ZFS send to someplace and have a backup (daily, maybe hourly). I'm thinking to put together a MINIMAL system to accept that backup. It will not support multiple users, or VMs, or Jails, or anything except receiving a backup and (hopefully never) restoring one. I've only got 1Gb networking in my house so that establishes the max throughput that this can ever achieve. What can I get away with on a system with those requirements?

I'm assuming that with 1Gb network 3Gb SATA II isn't a bottleneck
Can I have just a 2 core 2 thread system?
Just 4GB ram?
Could I enable ZFS encryption even if my processor doesn't support AESNI?
Would I be better able to do that if I skipped the TrueNAS and just installed a barebones FreeBSD or is the webGUI inconsequential to the system requirements?

 

[sretalla]

Can I have just a 2 core 2 thread system?

Sure

Just 4GB ram?

No, 8GB minimum for ZFS or stability will be a problem.

Could I enable ZFS encryption even if my processor doesn't support AESNI?

If the intent is just to receive the replica, you don't need to process the decryption on that system anyway, you can send back the replica without ever decrypting the blocks.

Would I be better able to do that if I skipped the TrueNAS and just installed a barebones FreeBSD or is the webGUI inconsequential to the system requirements?

As per the RAM question, the minimum RAM requirement is about ZFS, not FreeNAS/TrueNAS.

 

[gth871r]

So, what is the deal with zfs ram requirements? According to the FreeBSD FAQ the minimum is 4GB. https://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/all-about-zfs.html
But everyone here insists that you have to have at least 8. Is there something special about FreeNAS that makes it more intensive? I run a pfSense router that has a zfs boot drive and only 4gb ram after several months no problems. Am I playing with fire on that machine?