I was tasked a while ago with rebuilding our home made NAS server.  Given my options, I went with a RAID-6 config.  Why?  Here’s why: http://www.zdnet.com/blog/storage/why-raid-5-stops-working-in-2009/162 RAID 6 is the way to go these days.  Minimum.  And thankfully we did, as one of the hard drives went bad within a month.