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What are the different widely used RAID levels and when should I consider them?

I haven't had any trouble building mental images of the simpler RAID forms, but for some reason my head spins when I try to think about 10. Let me walk through my conception:

Mirroring is obvious: N drives, each with a copy of the same data X. So for N=2, we have D(isc) 0 with Xcopy0, and D1 with Xcopy1.

Striping is obvious: N drives, each with 1/Nth of each byte. So for N=2, we have D(isc)0 with Stripe0 having every nybble 0, and D1 with Stripe1 having every nybble 1.

For 10, let's say with 2-bit stripes (i.e., 4 discs), do we need 8 discs, where we mirror D0+D4, D1+D5, D2+D6, and D3+D7, and then stripe D0..D3 (and D4..D7, or does that come for free?).

Or does it work some other way?