Hi David,
We have been using RAID 1 (software) with RedHat 7.3 and 8.0 without any problems ... That's the cheapest solution you can get :)
We are using it on a server that is running a quite active PostgreSQL database and it's running very nicely.
I couldn't provide you with performance details to compare software vs. hardware RAID though but I haven't seen a particular slowdown compared to the server as it was before we did implement the RAID.
