Re: Software RAID level 1 issue

["3tcdgwg3" <3tcdgwg3@prodigy.net>]

This feature works only for raid1, or both raid1 and raid5?

Thanls.
W
----- Original Message -----
From: "Paul Clements" <Paul.Clements@SteelEye.com>
To: "3tcdgwg3" <3tcdgwg3@prodigy.net>
Cc: "Stef Telford" <stef@chronozon.artofdns.com>; "'Greg Rasberry'"
<rgreg-r@pacbell.net>; "'Linux raid mailing list'"
<linux-raid@vger.kernel.org>
Sent: Friday, May 30, 2003 1:31 PM
Subject: Re: Software RAID level 1 issue


> 3tcdgwg3 wrote:
>
> > If there is a plan to do a "intelligent resync", like some of the raid
> > controller
> > vendors offer?  The resync process will be hold on, if there are IO
requests
> > from upper level, and resumed when there is no IO.  By doing that, the
> > system
> > performance always be on the top.  I am very interested in  having
something
> > like that.
>
> This wasn't exactly what I meant by intelligent resync, but...I think
> what you're asking about is something that the md driver already does to
> some extent. It will slow down a resync if there is active I/O on the
> device. This can even be tuned by the user by manipulating a couple of
> kernel sysctls:
>
> apache:~# cat /proc/sys/dev/raid/speed_limit_min
> 100
>
> apache:~# cat /proc/sys/dev/raid/speed_limit_max
> 10000
>
> apache:~# echo 1000000 > /proc/sys/dev/raid/speed_limit_max
>
> apache:~# cat /proc/sys/dev/raid/speed_limit_max
> 1000000
>
>
> These are in KB/s.
>
> The "min" refers to the maximum I/O bandwidth that will be consumed by
> resyncs before the resyncs get throttled, when there is other I/O
> activity on the device.
>
> The "max" refers to the maximum I/O bandwidth that will be consumed by
> resyncs before the resyncs get throttled, even if there is no other I/O
> activity on the device.
>
> --
> Paul