From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: device queue scheduler Date: Thu, 18 Mar 2010 12:49:17 -0400 Message-ID: <4BA2598D.8040503@cfl.rr.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: 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 I'm wondering why the dm block devices have a request queue at all, and more importantly why they use the default cfq scheduler. It seems to me that the physical disk should take care of the scheduling, and not have that work duplicated at each layer of dm stacked on top. It wonder though, where should the scheduler policy be set? In libdevmapper, or by a system udev rule?