Re: Raid 0 Swap?

[Kyle Moffett <mrmacman_g4@mac.com>]

On Sep 05, 2006, at 19:44:30, Bill Davidsen wrote:
> Final note: if you are building a really reliable system, RAID6 on  
> all data, redundant power supplies (the highest point of total  
> failure), then you should go to RAID0 for swap, on multiple  
> controllers, preferably one drives in different enclosures. RAID6  
> for swap sucks rocks off the bottom of the ocean, three way RAID1  
> performs well even after a one drive failure.

There's also some interesting high-performance FPGA-based products  
out there which stack another layer or two of reed-solomon coding on  
top of a group of N existing drives so that you can handle up to M  
drive failures where M < N, and optionally also a failure of a stripe  
of up to K sectors out of every group of J sectors.  IIRC your  
average CD and DVD uses this kind of encoding, so if you have a bunch  
of scattered errors or a single big error up to like 9k long you can  
still recover all the data while decoding.  Those kind of matrix  
transformations would be dog-slow on a general purpose CPU, but with  
custom FPGA or VLSI chips you can do it in parallel easily better  
than disk bandwidth

Cheers,
Kyle Moffett
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