From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Hardy Subject: Re: raid reconstruction speed Date: Thu, 19 Jan 2006 14:10:02 -0800 Message-ID: <43D00E3A.5090102@h3c.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids PFC wrote: > When rebuilding md1, it does not realize accesses to md0 wait for > the same disks. Thus reconstruction of md1 runs happily at full speed, > and the machine is dog slow, because the OS and everything is on md0. > (I cat /dev/zero to a file on md1 to slow the rebuild so it would > let me start a web browser so I don't get bored to death) echo "10000" > /proc/sys/dev/raid/speed-limit-max (or similar?) You can do that in /etc/rc.local or something to make sure it sticks, then you'll be able to use your machine while any array rebuilds. I guess the feature you're asking for is for md to guess that accessing any partition component on a disk that has a partition being rebuilt should throttle the rebuild, right? Can that heuristic be successful at all times? I think it might. Does md have enough information to do that? I don't know... -Mike