On 1/17/2013 9:51 AM, Mikael Abrahamsson wrote: > The probability of getting struck by lightning is a lot less than being > struck by a read error when rebuilding from the only remaining mirror > when one drive failed and you've replaced it. The probability of a URE during rebuild increases with the number and size of the source drives being read to rebuild the failed drive. Thus the probability of encountering a URE in the 1:1 drive scenario is extremely low, close to zero if you believe manufacturer specs. > <http://www.zdnet.com/blog/storage/why-raid-5-stops-working-in-2009/162> > is applicable to RAID1 and RAID10 as well as RAID5. In Robin's example we're reading 12TB of sectors from 6 drives to complete the rebuild of one failed drive, so the overall probably of a URE is less than that of a single drive. With RAID1/10 we're only reading 2TB, well below the URE rates for single drives. So, no, the "URE scare" being propagated these days doesn't affect RAID1/10. If/when individual drive capacities exceed 10TB in the future, and if at that time the URE rates per drive do not improve, -then- this phenomenon will affect RAID1/10. But it does not currently with today's drives. -- 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
