From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751982Ab1IBMwN (ORCPT ); Fri, 2 Sep 2011 08:52:13 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:42203 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845Ab1IBMwL (ORCPT ); Fri, 2 Sep 2011 08:52:11 -0400 X-AuditID: b753bd60-a1479ba0000050a4-71-4e60d177ccae X-AuditID: b753bd60-a1479ba0000050a4-71-4e60d177ccae Message-ID: <4E60D16A.8060802@hitachi.com> Date: Fri, 02 Sep 2011 21:51:54 +0900 From: Nao Nishijima User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:6.0) Gecko/20110812 Thunderbird/6.0 MIME-Version: 1.0 To: Valdis.Kletnieks@vt.edu Cc: Tejun Heo , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Jens Axboe , James.Bottomley@HansenPartnership.com, dle-develop@lists.sourceforge.net, Masami Hiramatsu , yrl.pp-manager.tt@hitachi.com, kay.sievers@gmail.com Subject: Re: [-v3 PATCH 0/3] Persistent device name using alias References: <20110825090359.2288.91057.stgit@ltc197.sdl.hitachi.co.jp> <20110825101602.GI3286@htj.dyndns.org> <4E58C3BD.3000609@hitachi.com> <20110827102655.GJ2632@htj.dyndns.org> <4E58E905.4020704@hitachi.com> <16628.1314734537@turing-police.cc.vt.edu> In-Reply-To: <16628.1314734537@turing-police.cc.vt.edu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Valdis, (2011/08/31 5:02), Valdis.Kletnieks@vt.edu wrote: > On Sat, 27 Aug 2011 21:54:29 +0900, Nao Nishijima said: > >> A kernel device names (e.g. sda) is not useful information because it >> doesn't always point the same disk at each boot-up time. > > If this is important to you, can't you use a udev rule, similar to what most > distros already stick in 70-persistent-net.rules and 70-persistent-cd.rules? > > (Yes, this *does* involve finding a UUID or label or something on the disk > that you can identify as "same entity as last time". As you said, it is able to identify a disk at the expense of checking cost. However to introduce "alias" is an advantage of reducing both the cost and the risk of miss-communication, and it can easily identify it. And also, currently, kernel log and command output do not accord with the device name which a user uses (e.g. by-id, by-uuid). I would try to solve those mismatches using "alias". In other words, I'd like to introduce aliases for integrating the name of devices to control and record. Of course I will modify commands using a device name to use a persistent device names. Best regards, -- Nao NISHIJIMA Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., YOKOHAMA Research Laboratory Email： nao.nishijima.xt@hitachi.com