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From: Mike Hardy <mhardy@h3c.com>
To: linux-raid@vger.kernel.org
Subject: Re: raid reconstruction speed
Date: Thu, 19 Jan 2006 14:10:02 -0800	[thread overview]
Message-ID: <43D00E3A.5090102@h3c.com> (raw)
In-Reply-To: <op.s3m9znsqcigqcu@apollo13>


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

  reply	other threads:[~2006-01-19 22:10 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-19 12:02 Handling of read errors in raid6 Filipe Maia
2006-01-19 20:39 ` attempt to access beyond end of device PFC
2006-01-19 21:29   ` raid reconstruction speed PFC
2006-01-19 22:10     ` Mike Hardy [this message]
2006-01-19 23:27       ` Mark Hahn
2006-01-19 22:27     ` Neil Brown
2006-01-19 22:37       ` PFC

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