On 06/10/2012 09:26 PM, plug bert wrote: > hi peeps, > > i've been reading through > > http://en.wikipedia.org/wiki/Non-standard_RAID_levels > > and just wanted to verify if my understanding is correct. > > Is "near" safer than "far"? > > e.g. given 4 drives in RAID10 array, n2: > > 4 drives > > 1 2 3 4 > -------------- > A1 A1 A2 A2 > A3 A3 A4 A4 > A5 A5 A6 A6 > A7 A7 A8 A8 > > you'd lose the array if either 1&2 or 3&4 goes down at the same time. > > > With 4 drives in RAID10 array, f2: > > 4 drives > 1 2 3 4 > -------------------- > A1 A2 A3 A4 > A5 A6 A7 A8 > A9 A10 A11 A12 > .. .. .. .. > A4 A1 A2 A3 > A8 A5 A6 A7 > A12 A9 A10 A11 > > ...there seems to be a lot more combinations that can result in a trashed array(1&2, 2&3, 3&4). > > Is my analysis correct? Inputs are more than welcome, tia I think wikipedia might have this layout wrong. I was under the impression that a four-disk far2 layout would be: > 1 2 3 4 > -------------------- > A1 A2 A3 A4 > A5 A6 A7 A8 > A9 A10 A11 A12 > .. .. .. .. > A2 A1 A4 A3 > A6 A5 A8 A7 > A10 A9 A12 A11 I haven't checked the code, though. Phil -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
