RAID-3? (was: cvs commit: src MAINTAINERS)

Kenneth D. Merry ken at
Fri Aug 20 15:35:12 PDT 2004

On Fri, Aug 20, 2004 at 21:35:47 +0200, Pawel Jakub Dawidek wrote:
> As you can see RAID5 is only faster in READ tests for 15 and 100 processes
> working in parallel. As I can see, RAID3 is faster in all the rest tests.
> Of course you are welcome to try by yourself.
> Anyway, if I can ask for something. Think twice before calling something
> ridiculous without understanding.
> PS. I wonder about read optimization, so parity component can be also
>     used for reading in round-robin fashion...

That likely wouldn't speed things up too much.  The hard drives are doing
read ahead anyway, so they'll usually have the data ready when you go down
to read the next block if you're doing sequential reads.

You would also spend more CPU power to reconstruct the piece of data you
didn't read from the disk.  That'll probably increase your latency
somewhat, and you would also be touching all of the data with the CPU.

As PHK said, it might be more interesting to do data integrity checking on
reads.  The problem, of course, is that you wouldn't be able to correct
problems, you would only be able to detect them.

Kenneth Merry
ken at

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