zGreenfelder wrote: > On Mon, Mar 4, 2013 at 11:20 AM, John Plemons <john at mavin.com> 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