[OpenIndiana-discuss] Recommendations for fast storage

[Jim Klimov]

On 2013-04-17 20:09, Jay Heyl wrote:
>> reply. Unless the first device to answer returns garbage (something
>> that doesn't match the expected checksum), other copies are not read
>> as part of this request.
>>
>
> Ah, that makes much more sense. Thanks for the clarification. Now that you
> put it that way I have to wonder how I ever came under the impression it
> was any other way.


Well, there are different architectures, so some might do what you
suggested. From what I read just yesterday, RAM mirroring on some
high-end servers works indeed like you described - by reading both
parts and comparing the results, testing ECC if needed, etc. to
figure out the correct memory contents or return an error if both
parts are faulty and can't be trusted (ECC mismatch on both).

Military, nuclear and space systems often are built like 3 or 5
computers (odd amount for easier quorum) doing the same calculations
over same inputs, and comparing the results to be sure of them or to
redo the task.

So I guess it depends on your background - why you thought this of
disk systems ;)

//Jim