zGreenfelder wrote:
> On Mon, Mar 4, 2013 at 11:20 AM, John Plemons <john@xxxxxxxxx> wrote:
>> Raid 10 is a mirrored stripped set of at least 4 driver. You get the
>> best of both worlds, data speed and data back up..
>
> yeah, that's the industry standard. he's asking you to go find and read
> http://en.wikipedia.org/wiki/Raid10#Near_versus_far.2C_advantages_for_bootable_RAID
> wherein they mention that linux md devices can do what they call a
> raid 10 on 2 drives. and then details some of the reasons you might
> want to do such a thing.
>
> I can't see any reason to go with the sorta raid 10 on only 2 drives.
> from that article, I'd the only sane choice for raid 10 on 2 drives
> is the 'far' config on SSD drives. but that's just my opinion. I
> don't think I'd ever pick raid10 on 2.
>
> from the entry:
> "...copies of a block of data are "near" each other or at the same
> address on different devices or predictably offset: Each disk access
> is split into full-speed disk accesses to different drives, yielding
> read and write performance like RAID 0 but without necessarily
> guaranteeing that every stripe is on both drives"
>
> which then some (and by murphy's rule will be the most critcal) will
> go from being raid 10 to raid0. and likely 0 on the drive that fails.
AHHH! I didn't read closely enough, and missed that lack of guarantee.
Thanks, *that's* the kind of discussion I was looking for.
mark
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