2 servers are set up raidz2 with 4 disks per server. So about 6-7 TiB of actual storage space.
The servers do dns, mysql, and smb via plugins and a jail.
the primary backs up to the secondary every evening.
All the TVs in the house are really xbmc clients connecting to the SMB shares and mysql.
The most expensive part of it is the 8ea 4T HDDs.
Unless you have 10 people in your house watching different TVs at the same time, you can use real low end computers.
disks are $150 ($120 if you get externals on sale from huevonuevo & open the box). Excellent computer for this is a Dell poweredge T20 ($300).
These T20s have ECC RAM (you want this)
Anyhow 8*150 + 2*300 + a hundred bucks for misc. cables, bootable memory stick, maybe a switch...
Under 2 grand for the whole mess. Put one in your basement and one in your attic. Then you are protected from a flood or a tornado--but not both together.
If your house burns down, though, you're hosed
Upgrade plan is to "destroy" (that's the command...) the zpool in the secondary then change it from raidz2 with 4 disks to raidz2 with 6 disks.
let rsync do its thing, then swap the usb keys with the embedded OS.
Repeat with the old primary which will now be the secondary.
Already tried this once; works no problem. At any given moment I'm tolerant to at least 2 disk failures.