On 19/03/17 18:35, Gandalf Corvotempesta wrote: > As I would like to replace most of our HW raid controller with mdadm, > any suggestion on how to improve RAID-6 speed ? Burst speed, or sustained speed? Big difference ... > > Modern CPU aren't an issue, I don't think that double-parity > calculation could create any bottleneck on a modern CPU. Using a journal on an SSD will offload stuff and give you a decent burst speed, I suspect. You'll need to get benchmarks, but that should mean you don't notice a slow background write speed. > The real advantages of a raid controller are mostly 2: > > 1) the writeback cache (1GB or 2GB) > 2) the ability to automatically replace a disk by hotswapping it. > > Any solution to this ? For the "2", i've tried by configuring the > POLICY in mdadm.conf but new disk is never reconized and I always have > to manually add the new disk to the array. I think you have to manually add the disk to the array (group) as a spare first. And I would avoid that entirely if I can - put the new disk in, do a --replace, and then remove the old one. Doing a hotswap like that will increase the stress on the array, and increased stress means another disk is more likely to fail. Cheers, Wol -- 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
