Re: 3-way mirrors

[Tim Small <tim@seoss.co.uk>]

On 07/09/10 15:19, George Spelvin wrote:
> After some frustration with RAID-5 finding mismatches and not being
> able to figure out which drive has the problem, I'm setting up a rather
> intricate 5-way mirrored (x 2-way striped) system.
>    

I know that this doesn't solve your current problem, but I wondered if 
the fact that mismatch_cnt is not a reliable indication of corruption on 
RAID1 and RAID10 is a problem with your proposed solution?  I don't know 
how difficult it would be to fix that whilst you are at it (add a data 
copy in the write path).

Whilst I think about it, perhaps mismatch_cnt should be dropped from 
RAID1 / RAID10 entirely, as it doesn't seem to be particularly useful 
as-is....

Perhaps the data-copy mode could be a runtime option, and mismatch_cnt 
would only appear when it was switched on (and a repair forced when 
making the transition from no-copy mode to copy mode?).

Cheers,

Tim.


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