I have RAID controller with 24 SATA disks. Which configuration is faster?
- One RAID5 with all disks.
- Six RAIDs with 4 disks in each group.
To answer: Option 2 is faster than Option 1.
With one group of 24 discs, RAID5 will limit your writes to the speed of the one disc for parity, which is likely to become a bottleneck on any sensible activity. With 6 groups, there are obviousl 6 independent parity discs, so your write performacne theoretically is about 6 times as high.
That said, I would consider such a setup highly inefficient. There is a lot between sky and earth, so to say. I would possibly try mitigating the bad write performance through other means.
Neither - R5'ing 24 disks is a recipe for disaster, in fact many RAID controllers won't even let you create a single R5 array with more than around 14 disks, the risk is too great. And the 6 x 4 R5's makes no sense either.
You don't mention your definition of performance but if you want the fastest configuration then R10 is the way but presumably you don't want to lose 12 disks worth of space (although the 6 x 4 would lose you 6 right), If I couldn't go for R10 then I'd go for R50 or R60, losing either 2 or 4 disks space myself.
As this is very dependant on the actual controller you have, the only answer is "measure them both ways and see for yourself".
With 24 spindles, I wouldn't use RAID5 myself anyway, but that's kinda besides the point.