On Tue, Jun 11, 2019 at 04:11:52PM +0800, Guoqing Jiang wrote: > Hi, > > On 6/11/19 3:43 PM, keld@xxxxxxxxxx wrote: > >thanks for this patch > > > >I think we should change the hd algorithm to chose the highest block > >number at least for the > >far layout. ther outer blocks have the fastest transfer rates and also the > >shortest > >distance for head movement. > > I didn't investigate the performance of far layout a lot, seems there > was one patch > (commit 8ed3a19563b6c " md: don't attempt read-balancing for raid10 > 'far' layouts") > which was aimed to do it, and you were the author, no? ;-). Or I missed > something. yes , I was the author of that patch. and it solved the problem: to get the drives to stripe, evne if the hd drives have different transfer rates and rotation speeds. what I think I got wrong was that it was using the inner parts of the disks instead of the outer parts, where the transfer rate is higer and head movement less. I am suggesting now to reverse this. keld
