I currently have a 6 disk RAID5 setup with a heterogeneous mix of 300 GB hard drives (maxtor, samsung, western digital). I use a 3Ware 9650SE-8 hardware RAID card and have the battery backup.
This setup gives me roughly 1.5 TB of usable storage. I also have a 1.5 TB hard drive. I plan on using either the 1.5 TB drive as my backup, or use it as my primary and start using the 6x300GB hard drives as my backup.
These days, I mostly use my computer for playing games. So, if I want to, say, minimise my Windows and TF2 start up time, that sort of thing, which option is best? Use single 1.5TB drive for my system? Or use 6 disk RAID5 setup?
Since you already have so many hard drives, I'd say put 3 hard drives to use for the OS using Raid5. Use either 2 or 3 of the remaining hard drives for a raid 0 array for games. Keep the 1.5tb as backup. I wouldn't recommend this to anyone having to buy the drives, but since you already have the drives, why not?
Your startup/load times in games will be a rather negledgable increase with RAID. So personally id be using the big drive for everything and the RAID-5 as a backup, btw is the RAID-5 on a seperate machine because if its on the same machine it isnt really a backup as if you machine dies (motherboard or controller) then you still dont have access to your drives.
If I use the 1.5 TB drive as my primary, I'll move all the 300 GB hard drives to a secondary machine which will basically just serve as a backup. I'll also most likely ditch my hardware RAID card, just use software RAID5 on the secondary machine. The 256 megs of cache on the RAID card is nice but not a huge win.
My recent experience has shown that to have a good backup, you need to eliminate all single points of failure. So I'll either have the 1.5 TB drive in my desktop and all others in a secondary machine, or the other way around. I mean, they'll both be plugged in to the same power grid and in the same house (data not sufficiently valuable for off-site backup), but that's all.
For roadrunner197069, not sure what my current HD transfer speeds are. Toms Hardware benchmarks show access times are likely to increase from about 14 ms to 30 (single drive to RAID) but the rest of the specs would improve.
For br3nd064, I actually have a WD Raptor as well, probably start using that for the OS and games.
At this point, I'm most likely going to start using the 1.5 TB drive on my desktop, move the 300 GB hard drives to my secondary machine and use that to back up my desktop, and sell my 3ware 9650SE-8LMPL (and battery backup module) on eBay.
RAID5 has parity and will serve as a better backup than a single drive will. With a single drive, if it fails, the data is lost. On RAID5, if a single drive fails, you can rebuild the data with parity from the others. So out of the options you mentioned, the backup should probably be on the RAID5.
As for what you should do with all your gear, since you have a Raptor, you should probably put your OS/Games on that thing. Put your RAID5 backup in a different machine. Connect via LAN to backup things to it (just make sure you have 10/100/1000 lan options or better). For OS/Games, you don't need 1.5 TB. Not even close.
OS/Games: The Raptor.
Storage: The 1.5 TB single drive.
Backup: RAID5 in another system, connect via LAN to backup.