From: "\"Ramon Schönborn\"" <RSchoenborn@gmx.net>
To: NeilBrown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Subject: Re: md device io request split
Date: Wed, 23 Nov 2011 14:22:16 +0100 [thread overview]
Message-ID: <20111123132216.162860@gmx.net> (raw)
In-Reply-To: <20111123133124.2042c1f4@notabene.brown>
> RAID1 will only limit requests to 4K if the device beneath it is
> non-contiguous - e.g. a striped array or LVM arrangement were consecutive
> blocks might be on different devices.
how does it know if a device is non-contiguous? Is there a way to have a dm device "marked" like that or force md to use bigger requests?
Lets assume a host with about 20 raid1 devices consisting of dm-devices with the mentioned overhead - do you think that not splitting the requests could lead to a noticeable performance improvement?
Thanx for your help,
Ramon Schönborn
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next prev parent reply other threads:[~2011-11-23 13:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-22 9:36 md device io request split "Ramon Schönborn"
2011-11-23 2:31 ` NeilBrown
2011-11-23 13:22 ` "Ramon Schönborn" [this message]
2011-11-23 19:30 ` NeilBrown
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