From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bryn M. Reeves" Subject: Re: raid1 round-robin scheduler Date: Fri, 5 Dec 2014 14:34:59 +0000 Message-ID: <20141205143458.GD16315@localhost.localdomain> References: <20141205130239.GC16315@localhost.localdomain> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On Fri, Dec 05, 2014 at 05:08:59PM +0400, Vasiliy Tolstov wrote: > 2014-12-05 16:02 GMT+03:00 Bryn M. Reeves : > > iirc the patches showed no measurable performance gain. > > > > Regards, > > Bryn. > > > Yes in normal read speed not changed, but in case of fully loaded > system when one member fully utilized by io, why performance in this > case not increased? I don't think this was ever really explained but the testing that was done failed to show a benefit from the patches and as they added more complexity to the target for no gain they were not merged. As Zdenek says today the MD-based dm-raid targets are now available and those should expose all the features of the MD stack (including read balancing). Regards, Bryn.