From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alasdair G Kergon Subject: Re: [PATCH] Allow multipath devices to be created for readonly devices Date: Mon, 20 Jul 2009 21:08:36 +0100 Message-ID: <20090720200835.GE32330@agk-dp.fab.redhat.com> References: <200907081417.59976.knikanth@suse.de> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <200907081417.59976.knikanth@suse.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Nikanth Karthikesan Cc: device-mapper development List-Id: dm-devel.ids On Wed, Jul 08, 2009 at 02:17:59PM +0530, Nikanth Karthikesan wrote: > Currently we cannot create device-mapper tables for multipath devices > whenever they are read-only.This patch modifies the device-mapper to > set the 'READ-ONLY' flag automatically whenever a read-only is added > to the table. I recall discussing this before: 1) Contrary to the assertion above, you can already create such dm tables, by marking them explicitly as read-only. 2) The distinction between read-only and read-write device-mapper devices is currently clear and simple. This proposal replaces the definitions with far-less-intuitive ones and that is why I ignored it first time around. If you believe the existing interface and behaviour is inadequate, think about some alternatives: - What is the heart of the problem here? Give a specific example to show why we need improvements: Is the patch really about optimisation, arguing that to achieve the desired result through the current interface involves avoidable effort? - Consider whether adding another clearly-defined state to the system or extending the userspace interface would be a better approach. Alasdair