On 11/20/2013 8:46 PM, John Williams wrote: > For myself or any machines I managed for work that do not need high > IOPS, I would definitely choose triple- or quad-parity over RAID 51 or > similar schemes with arrays of 16 - 32 drives. You must see a week long rebuild as acceptable... > No need to go into detail here I disagree. > on a subject Adam Leventhal has already > covered in detail in an article "Triple-Parity RAID and Beyond" which > seems to match the subject of this thread quite nicely: > > http://queue.acm.org/detail.cfm?id=1670144 Mr. Leventhal did not address the overwhelming problem we face, which is (multiple) parity array reconstruction time. He assumes the time to simply 'populate' one drive at its max throughput is the total reconstruction time for the array. While this is typically true for mirror based arrays, it is clearly not for parity arrays. The primary focus of my comments was reducing rebuild time, thus increasing overall reliability. RAID 51 or something similar would achieve this. Thus I think we should discuss alternatives to multiple parity in detail. -- Stan -- 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
