Re: RAID-6 question.

["H. Peter Anvin" <hpa@zytor.com>]

Justin Piszcz wrote:
> 
> Yeah, one core was pegged at 100% for the resync, another (md_raidX)
> process
> was at ~35% on the second core.  The third and fourth core were unused
> but immediately when I start the resync it definitley slowed down the
> system quite a bit and hurt interactivity and as I mentioned before
> *without* specifying a lower rebuild speed than the system's maximum I/O
> the system is unusable until the rebuild completes, perhaps its a
> combination of using all of the one core for the resync where raid5 may
> not?  I recall w/raid5 I did not have to specify a lower limit for
> max_rebuild KiB/s..
> 

RAID-5 recovery can use the normal accelerated functions, whereas RAID-6
recovery can't (only a handful of CPUs have the operations needed to
accelerate dual-disk recovery, and even for those it is not implemented
at this point.)

	-hpa