I am planning to build a new computer and I wanted to get some advice on Raid5 and Raid 1+0.
* All but a few so called "Cheaper" NAS Raid devices have any decent transfer rates. i.e Gigabit networking doesn't necessarily mean Gigabit Transfer speeds, and most aren't anywhere close to a PC with the same.
* "Fake" Raid is common on many cheaper raid controllers and many built-in mainboard raid controllers. The upshot is that its just in enhanced software raid and many OS's don't support it well.
* I can recommend Adaptec SATA Raid controllers specially the 4, 6, or more port cards as they are hardware raid. (Sadly however Adaptec have been bought out so support will diminish.)
* Depending on the resilience you want Raid 1 and Raid 1+0 is the by far the most resilient, Raid 5 is much weaker, unless you use a hot spare.
