From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754890AbYIEPP1 (ORCPT ); Fri, 5 Sep 2008 11:15:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753784AbYIEPPP (ORCPT ); Fri, 5 Sep 2008 11:15:15 -0400 Received: from g4t0017.houston.hp.com ([15.201.24.20]:33100 "EHLO g4t0017.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753571AbYIEPPO (ORCPT ); Fri, 5 Sep 2008 11:15:14 -0400 Subject: Re: [PATCH 0/6] detect online disk resize From: Andrew Patterson To: Pasi =?ISO-8859-1?Q?K=E4rkk=E4inen?= Cc: linux-scsi@vger.kernel.org, James.Bottomley@HansenPartnership.com, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, andmike@linux.vnet.ibm.com, mike.miller@hp.com, genanr@emsphone.com, jmoyer@redhat.com In-Reply-To: <20080905082110.GN13941@edu.joroinen.fi> References: <20080904202714.10456.88061.stgit@bob.kio> <20080905082110.GN13941@edu.joroinen.fi> Content-Type: text/plain; charset=UTF-8 Date: Fri, 05 Sep 2008 09:15:10 -0600 Message-Id: <1220627710.7790.17.camel@grinch> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2008-09-05 at 11:21 +0300, Pasi Kärkkäinen wrote: > > 1. For SCSI devices do: > > > > # echo 1 > /sys/class/scsi_device//device/rescan > > > > or > > > > # blockdev --rereadpt > > > > 2. Other devices (not device mapper) > > > > # blockdev --rereadpt > > > > I have tested this patch on SCSI and SmartArray (cciss) > > devices. Device mapper still does not recognize device size changes > > until the device is restarted. > > > > Hello and thanks for the patch! > > How about device mapper.. what's needed to make it detect/support online resizes? > I'm specificly interested in online resizing (growing) dm-multipath devices.. > Yes, it would be nice if this patchset worked here too. It currently does not. > Basicly I'd like to have LVM PV on dm-multipath device.. so first I need to > get the actual disks resized, then dm-multipath device, and finally run pvresize. > I did some testing with multipath here. I could get it working by shutting down the devices, resizing all the underlying paths using the above methods, restarting the devices, then running pvresize. This method does not help much given that most users cannot realistically shutdown a device. This patch series works fine with standard LVM/dm, i.e., resize using one of the above methods, then run pvresize. I was planning on looking into dm-multipath in the near future. Mike Anderson has done some work in this area in the past. > I know dm-multipath part can be done atm using this (hacky) method: > https://www.redhat.com/archives/dm-devel/2008-August/msg00033.html > This is indeed ugly. It looks like they are pulling the paths out of the device, resizing them, and then adding them back in. > -- Pasi