Suggestions to build a NAS Server for backup from old PC

[Orestis_gr]

I am willing to build a NAS server for my office using and old PC. The Pc is using a less than a year old motherboad with a cpu AMD FX 8320 or something. Has around 8GB ram and will boot on an SSD 240GB.
I already use a small Dlink NAS "server" with 2x4TB raid1 for the backup.
The backup size I am willing to have on this server is at least 8TB and I am able to add an SSD for caching if that has a gain in the general setup.
The network for the time being is a small Gigabit switch on ym desktop. If I wish to move the NAS server in the storage room which is in general cool and aired I will have to use a gigabit cable or a DLink powerline which will never be 1gbit.


The drives I already have available are the following.

Backup NAS (backs up F and E)
4TB WD BLUE WD40EZRZ inside the NAS
4TB WD BLUE WD40EZRZ inside the NAS

Primary Drives I wish to backup
3TB Toshiba DT01ACA300 used for archive (Drive D:)
3TB WD WD30EZRZ used for archive (drive E:)
1TB NVME drive that syncs with laptop, used to work on current projects (Drive H:)

Backup Drive inside Desktop
3TB Toshiba HDWD130 (Drive F:) backsup drive D:

So from what I have been reading I should go with RaidZ2, should I get 3 more 4tb drives and have 5x4tb which will be almost 16GB?
What I wish for this setup is to backup and sync, I am not going to work on the NAS files and my backups will be some GB's each time, so the 1GB line is not an issue for me. I want to have piece of mind with my backup rather than great speeds.
I find many information but everytime I search it complexes me a bit.
THanks in advance for your help and time.

 

[WN1X]

8GB of RAM is less than the minimum required by TrueNAS (16GB). Specifically, what motherboard is contained in this system?

 

[Davvo]

In addition to the RAM issue, I don't understand the HDD part of your post.