Can someone please explain to me the whole concept of raid? And all different kinds of it? Which one yields the best performance? I heard that raid 0 is the best performance wise, is that true? How do you setup Raid? Do both drives have to be the same brand/speed?
Have a read over at Wiki and come back to me
Quick answers to your questions...
RAID arrays are a number of disks joined in a number of different config's for different purposes. Performance and Integrity
RAID-0 , 1 , 5 , 6 and JBOD are the most common but you can have combo's of different configs ie. RAID50 is raid-0 and 5 combined.
RAID-0 is generally regarded as best performance but sacrifices integrity
RAID arrays can be set a number of different ways. Software or Hardware. which can be set in the OS or through a controller (most mainboards these days support it and can be configured through BIOS and/or their individual config utility during startup).
Drives do NOT have to be the same size/brand/model/speed, however, this is generally preferred as this can effect the final setup of the array. different sizes is the main effector in the fact that you can potentially "loose" disk space.
I was going to shoot myself in the mind and try to explain all the common RAID levels, but instead I'll link you some sites I've used to learn a great deal myself.
And I won't be snotty, but yeah, I originally used Google searches to find these, and then Google again to find them again.
Go ahead and browse through those, learn what you can, and bring back specific questions for us all :-) Good luck!