Raid 0 - how many disks to optimize performance?

[Dustmann]

I am interested in setting up a raid 0 array with sata drives, and wonder what the performance increase would be with 3 or more drives? Theoretically adding more drives should improve performance, but is there a difference between an array of 2 or an array of 3+? I've been using a raid0 setup with 2 ata100 drives for a couple of years, and am upgrading soon. Also, I'm not worried about data safety, I have seperate drives that I store all of my important data on. The drives would store mainly the OS and games.

I'm thinking about either doing a setup with 2x 120/160gb drives or something like 4x 40/80gb drives. Is striping data across more drives going to actually slow down performance? And should I stick with even numbers or would 3 or 5 be ok (my mobo only has 4 ports)? Does anyone know of any charts or benchmarks relating to this?

[EzyStvy]

Raid O must be done in pairs with identical size drives.

Generally speaking, there is a point of diminishing returns. Going with 4 drives would be going past this point.

[glc]

Actually you can have a 3 drive RAID 0 - drives should be identical. If they aren't, each drive will be reduced to the capacity of the smallest drive. It's also somewhat sensitive to differences in the drive manufacturers, etc. so ideally the drives should be identical models, down to exact same firmware. There will be no performance increase with anything more than 2 drives as far as I know.

[doctorgonzo]

Yes, theoretically you can increase total bandwidth linearly by having more drives. It depends totally on the drive controller, though. I'm not sure about this, but I'm guessing the onboard RAID controllers on most consumer-level motherboards won't be able to handle more than two disks. Also, at some point you are going to overwhelm the total bandwidth available on the bus, be it PCI or PCI Express or HT.

At the same time, increasing the number of drives in the array will also increase the chance of the array being destroyed due to drive failure. I wouldn't even put an OS on a RAID 0 array unless it was totally backed up at least weekly.