From: "H. Peter Anvin" <hpa@zytor.com>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: Linux-Raid <linux-raid@vger.kernel.org>
Subject: Re: RAID-6 question.
Date: Mon, 17 Nov 2008 08:09:50 -0800 [thread overview]
Message-ID: <4921974E.8050508@zytor.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0811170440001.26146@p34.internal.lan>
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
prev parent reply other threads:[~2008-11-17 16:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-10 11:56 RAID-6 question Justin Piszcz
2008-11-10 16:02 ` Justin Piszcz
2008-11-17 0:29 ` H. Peter Anvin
2008-11-17 1:01 ` NeilBrown
2008-11-17 9:42 ` Justin Piszcz
2008-11-17 16:09 ` H. Peter Anvin [this message]
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