From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [lvm] [christophe.varoqui@free.fr: dm multipath target] Date: 19 Aug 2003 09:19:53 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1061302795.2134.7.camel@fuzzy> References: <20030819073926.GA423@fib011235813.fsnet.co.uk> <20030819094838.F8428@sistina.com> <1061283871.3f41e81f8226b@impt3-2.free.fr> <20030819115110.I8420@sistina.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from zeus.kernel.org ([204.152.189.113]:64226 "EHLO zeus.kernel.org") by vger.kernel.org with ESMTP id S272338AbTHSPys (ORCPT ); Tue, 19 Aug 2003 11:54:48 -0400 Received: from hancock.sc.steeleye.com ([65.114.3.137]) by zeus.kernel.org (8.11.6/8.11.6) with ESMTP id h7JELb630151 for ; Tue, 19 Aug 2003 07:21:37 -0700 In-Reply-To: <20030819115110.I8420@sistina.com> List-Id: linux-scsi@vger.kernel.org To: mauelshagen@sistina.com Cc: christophe.varoqui@free.fr, mge@sistina.com, SCSI Mailing List On Tue, 2003-08-19 at 04:51, Heinz J . Mauelshagen wrote: > On Tue, Aug 19, 2003 at 11:04:31AM +0200, christophe.varoqui@free.fr wrote: > No, device-mapper is designed completely generic (LVM2 as well BTW). > It will never contain any vendor specific hacks. We don't need it to contain any vendor code, but we do need an interface for vendor specific additions. How arrays accomplish a path switch is highly vendor specific. Some (like EMC) run all paths active, so nothing needs doing. Others need a specific command sent to the array down the path before the switch can be done. > Ghosts should report EIO in case of an unstarted LUN anyway ? > In case they are started they are supposed to report EPERM on IO because > they don't support any. This is awfully vendor specific again. I know, for example, the HP MSA array will report a check condition, not ready. I think we translate this to I/O error in the mid-layer (best we can do). This is why we'll do a better job of error reporting in fastfail. James