From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick Mansfield Subject: Re: [RFC] Multi-path IO in 2.5/2.6 ? Date: Tue, 10 Sep 2002 12:37:32 -0700 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20020910123732.A15175@eng2.beaverton.ibm.com> References: <20020910114257.A13614@eng2.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: ; from mochel@osdl.org on Tue, Sep 10, 2002 at 12:00:47PM -0700 List-Id: linux-scsi@vger.kernel.org To: Patrick Mochel Cc: James Bottomley , Lars Marowsky-Bree , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org On Tue, Sep 10, 2002 at 12:00:47PM -0700, Patrick Mochel wrote: > > On Tue, 10 Sep 2002, Patrick Mansfield wrote: > > > On Tue, Sep 10, 2002 at 10:21:53AM -0700, Patrick Mochel wrote: > > > Easy: you map the unique identifier of the device to a name in userspace. > > > In our utopian future, /sbin/hotplug is called with that unique ID as one > > > of its parameters. It searches for, and finds names based on the ID is. If > > > the name(s) already exist, then it doesn't continue. > > > > > > > > > -pat > > > > But then if the md or volume manager wants to do multi-path IO it > > will not be able to find all of the names in userspace since the > > extra ones (second path and on) have been dropped. > > Which is it that you want? One canonical name or all the paths? I supplied > a solution for the former in my repsonse. The latter is solved via the > exposure of the paths in driverfs, which has been discussed previously. > > > -pat For scsi multi-path, one name; without scsi multi-path (or for individual paths that are not exposed in driverfs) each path probably needs to show up in user space with a different name so md or other volume managers can use them. -- Patrick Mansfield