i'm toying with the idea of doing a software implemented RAID6 setup, as a means of avoiding the $500+ cost of a RAID controller... it will be an 8 drive setup, more than likely 1 TB drives, so 6 usuable drives with 2 parity bit drives... this is for personal use, so money is a factor and speed really isn't ... its entire function is to stream movies/TV to my popcorn hour media player, so any read speed greater than about 2 MB/sec is fine by me, so pretty dam slow in other words... i could care less about write speed, but again it should be more than fine

so my main question is what type of hardware should i be looking at to run a RAID6 software setup? i have an old box with a P4 3.2GHz in it, would this be enough processor for the job? i have 1.5GB RAM in it right now i believe, but i can get some more if need be (although i would imagine software RAID is heavy on the CPU and not so heavy on the RAM)

if there is anybody out there who has setup a similar system, i would love to hear your feedback

Hi
Unluckily I don't have a RAID6 - only RAID5. Here are some informations about it, hoping they might be useful.

PC 1)
4 sata drives, all 2.5 7200 rpm, all four connected to the onboard ICH10 controller, using SW-RAID5, 32k chunksize and ext3 filesystem.
An Intel 6420 doublecore CPU, 2.13Ghz, throttled down to 1.6Ghz, 4GB RAM.
Writing an 8GB file with "dd if=/dev/zero of=2delete.data bs=64k count=131072 && sync", speed between 70 and 90 MB/s with 12% CPU usage.
Doing a "cat file.data > /dev/null" ran with 10% CPU usage reading 130 to 150MB/s.

PC 2)
4 500GB sata drives, all 3.5 7200 rpm, all four connected to a Promise sata 300 TX4 controller (full SW-controller - using kernel drivers), 64k chunksize, XFS filesystem.
Intel Q6600 quad core, 2.4GHZ throttled down to 1.6Ghz, 4GB RAM.
Writing same as above consumed ~14%CPU, with speed of 80MB/s.
Reading same as above at 110MB/s using 7%CPU.
Free space on this drive is highly fragmented (I am writing and deleting all the time a lot of small files) - this together with the different filesystem and chunksize might explain the low speed.

As you said a SW-RAID 6 will put for sure more load on the CPU, and having 8 drives even more, but I think that your system will be able to handle it well.
SW-Raid itself doesn't almost use Memory - it's up to you how much RAM you want the OS to use for caching - can be configured somewhere in /proc (or /sys?). I use the default settings which are 5 - 10% of the total RAM.
Greetings.