Advice for Pool Configuration on TrueNAS Mini XL+

[SwisherSweet]

Hi folks, I'm considering ordering a TrueNAS Mini XL+ system to run as a backup server (Time Machine, Asigra, Rsync target). This is going to be used in a small home office / small business with a few users. My goal is to be able to have safe backups, while also being able to affordably expand storage as time goes on. So I see my options as:

1. 1 x 8 Drive RAID-Z2
2. 2 x 4 Drive RAID-Z1

I understand I will have the most resilient setup of the two if I go with option #1. However, if I want to expand my storage, I have to replace all 8 drives to do so. But, if I go with option 2, I just need to replace 4 drives, but my data is not as resilient. From understanding as well is there are also performance differences with these two options, but I don't know that those will be material to me since this is just a backup server.

Also, I believe this server comes with two internal SATA slots and an NVMe slot. I was considering using the two internal SATA in a mirror (3 way if I can tap into a 3rd SATA port somewhere) for a Metadata vdev and the NVMe slot for cache. Again, given this is just a backup server, not sure I really need these but I have a bunch of spare SATA and NVMe drives, so it might help with Time Machine backup times.

Do you have any recommendations on pool configuration given what I shared?

Thank you.

 

[Etorix]

Easy advice: Go for safety, and do not bother with metadata and L2ARC on a backup server.
I'm sure you can find more useful purposes for your spares.