BUILD Build specs, and is my math for hard drive space correct?

[jimmyt]

Case - Node 304
Mobo - AsrockRack EC3224D2I
CPU - Pentium, G3258
Power supply - Seasonic G360
Ram - 16gb 2x8 ECC Crucial memory
USB Drive - Sandisk Cruzer FIT 16gb (Costco had them 2 for $8.. damn good deal)
Drives...all thats missing

I think I am going to go with 4 WD Greens 4TB (WD40EZRX) (WDidled of course) With the google wallet app, a few newegg gift cards and a promocode, I get get them for $115 each which seems like a good deal :)

If I do RaidZ2, I should have around 8TB usable correct? and If I opt for RaidZ1 then I am looking around 12TB? Is that correct or did I missing something. Isnt Z2 with 4 drives basically a mirror set?

I know the size is not truly 4TB, but you get my point :)

8tb will be more than enough for the forseeable future - I think I will go with Z2 and anything more is a bonus if my math is wrong.

How I will use the nas -
The nas is a backup for the pc's in the house - photos and documents and the like get stored on the desktop pc and backed up to the nas. I am also ripping blu rays and will store them on the nas as well. No plex or transcoding.. just streaming to to the htpc. once the movie is watched it usually gets deleted unless its a keeper then it gets mkv'd down to 4gb or so and stored (on the nas) where is may sit for a year before it ever gets watched :) I also have a few security cameras that write to the nas. they use 100gb each and store abot 60 days of data. Its really no big deal if the nas craps out (well it is.. but the lost data is also elsewhere) . As long as the nas, desktops and external drive that runs crashplan at my office all dont die at the same time :) Right now i have an old makeshft core2 pc with 4gb of non ecc ram running 2 1tb drives as a test freenas server and its been great.. no problems. I am even able to almost max out the gb network connection. :) with the new hardware, it should be smooth sailing

thanks for any advice!

 

[Mlovelace]

Isnt Z2 with 4 drives basically a mirror set?

No, stripped mirrors with 4 disks will result in the same pool size but is quite different then raidz2. In a raidz2 you can loose two disks in the vdev without loosing the zpool so it's better protection against data loss.

 

[marbus90]

^ whereas with striped mirrors you have a 2 out of 3 chance to survive a 2 disk loss.

If you ever plan on upgrading from 4 to 6 disks, it's easier to start with striped mirrors. Those you could expand with another mirrorset. You can't expand an existing raidz with more disks, just bigger ones. Starting out with 6x2TB raidz2 you would get 8TB and the chance to upgrade - just swap out all disks for bigger ones.

There are rumors that in the coming FreeNAS versions some features are mandatory which aren't available on the Pentium. If bugded allows it, have a look at the i3-4150/i3-4160.