SATA controllers

[Tom H]

>> I'm speccing a new machine and as part of it I'd like to have a
>> linux-controlled 4-disk RAID 6 array using SATA 3 Gbps disks (aka STA 2).

> You want more than 4 disks for RAID6. Seriously.

A valid point! I had COMPLETELY missed that... :)


> RAID6 uses 2 parity drives; this means you get the capacity of (N-2)
> drives, where N is the number of drives. Ergo, use 4 drives, you only
> get the capacity of 2. This is pointless, because if you lose half the
> capacity, you would get /much/ better performance from RAID10 (a
> mirror of stripes) or RAID 0+1 (a stripe set of mirror pairs).
> (I may have got the definitions of 0+1 and 10 transposed, but it's not
> really important at this point!)

You are right and I am 99% sure that you have the definitions
transposed; but I would have to look it up to be 100% sure because I
have the same problem with these 1+0 and 0+1 things.