Best RAID solution?

I just built up my own NAS using freeNAS from www.freenas.org and it works very well. It's a nice solution and if you shop smart it won't cost your an arm and a leg (just one or the other -- cost me $600 complete with drives for 2TB with backup). I use ZFS and 1 bit parity. So now if one of the drives fail, it will not only detect it, it will email me and I can replace it. It would take two drives for it to fail and for me to lose data. I considered using unRAID from www.lime-technology.com and it looks good but the OS costs money if you want more then 3 drives. The nice thing is, if you get a decent case for the computer you can add more internal drives as you need space and just keep expanding. As I was saying, with unRAID you need to buy it if you want more then 3 drives; but freeNAS you can just keep adding.

Now, you do need to know what you're doing to set these things up, they aren't perfect or 100% easy. There are a ton of advanced features I haven't played with yet, but so far, it hasn't been THAT difficult.

All this being said, there are several nice prebuilt raid servers out there. The Synology DS509+ is a nice machine and about the same price as building your own. http://www.synology.com/enu/products/DS509+/index.php

Good Luck.