First FreeNAS build

[Zmej]

Hi guys,

I'm planning to build my first home server running FreeNAS. Since I'm new at this I would like to get some other people's opinion before doing something stupid.
The use cases would be:
- Automatic backups from 2-4 PCs
- Media server(Plex, 1-2 streams max)
- Torrent server(with automatic download for my favorite series)
- I'm travelling a lot so a VPN server would also be useful(Is there any reason to run cloud server too?)

I wouldn't say that I'm on a budget and I have never bought any used electronics before, but this time I decided to go with used parts(HDDs will be new) and I would like it to be as low budget as possible because I will be probably replacing it in a few years(2 years max). At my home everything is Gb compatible(router, PCs, cables), so I would like to use this speed as much as I can.
I found a deal for a used i3-4130T+mobo+case+psu+8GB RAM for only 200$ and I would like to go with that. CPU seems to be good enough for 2 1080p streams and also has a low TDP. The ram is 1 stick so if needed I can easily upgrade if it is not enough. It will not be ECC because that would kill the budget. For my really important data I have backups on external drives, so a small risk of data loss is acceptable for me. For a boot drive I have an 500GB 2.5 HDD which was never used before. Any reason why not to use it as a boot drive?
Regarding storage at first I wanted to go with 3x2TB WD Reds in RAIDZ1, but maybe 2x4TB with mirroring would be a better option. Now I only need 4TB of useful space, but maybe in the future I will need more(one more reason for the 4TB drives).

Do you see any flaws with this build considering the use cases and that it needs to last only a year or 2?

 

[Chris Moore]

It will not be ECC because that would kill the budget.

The price delta between non-ECC and ECC is not so much. This is only because you are buying a package deal.

For a boot drive I have an 500GB 2.5 HDD which was never used before. Any reason why not to use it as a boot drive?

No, if you don't mind wasting some space, I would still suggest a mirrored boot pool so a single disk failure doesn't spoil the fun.

Now I only need 4TB of useful space,

If you need to be able to use 4TB of space, you need more than 4TB of 'raw' space because ZFS has overhead space that it uses for checksum data and you are not supposed to fill the pool beyond 80% due to the copy-on-write nature of the file system.
Here is an easy to use space calculator that will help you figure out what you need: http://wintelguy.com/zfs-calc.pl