On Jan 9, 2014, at 5:41 AM, Duncan <1i5t5.dun...@cox.net> wrote:
> Having checksumming is good, and a second 
> copy in case one fails the checksum is nice, but what if they BOTH do?
> I'd love to have the choice of (at least) three-way-mirroring, as for me 
> that seems the best practical hassle/cost vs. risk balance I could get, 
> but it's not yet possible. =:^(

I'm on the fence on n-way. 

HDDs get bigger at a faster rate than their performance improves, so rebuild 
times keep getting higher. For cases where the data is really important, 
backup-restore doesn't provide the necessary uptime, and minimum single drive 
performance is needed, it can make sense to want three copies.

But what's the probability of both drives in a mirrored raid set dying, 
compared to something else in the storage stack dying? I think at 3 copies, 
you've got other risks that the 3rd copy doesn't manage, like a power supply, 
controller card, or logic board dying.


Chris Murphy

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