Hi, On Fri, May 31, 2019 at 09:43:35AM +0800, Guoqing Jiang wrote: > On 5/30/19 3:41 AM, Andy Smith wrote: > >By contrast RAID-10 seems to split the IOs much more evenly: 53% hit > >the NVMe, and the average IOPS was only 35% that of RAID-1. > > > >Is this expected? […] > There are some optimizations in raid1's read_balance for ssd, unfortunately, > raid10 didn't have similar code. Thanks Guoqing, that certainly seems to explain it. Would it be worth mentioning in the man page and/or wiki that when there are devices that are very mismatched, performance wise, RAID-1 is likely to be able to direct more reads to the faster device(s), whereas RAID-10 can't do that? Is it just that no one has tried to apply the same optimizations to RAID-10, or is it technically difficult/impossible to do this in RAID-10? Thanks, Andy
