From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8495C61DA4 for ; Thu, 2 Feb 2023 20:48:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232692AbjBBUsh (ORCPT ); Thu, 2 Feb 2023 15:48:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233146AbjBBUsZ (ORCPT ); Thu, 2 Feb 2023 15:48:25 -0500 Received: from mx.ewheeler.net (mx.ewheeler.net [173.205.220.69]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60E23790A1 for ; Thu, 2 Feb 2023 12:48:16 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by mx.ewheeler.net (Postfix) with ESMTP id F1D4548; Thu, 2 Feb 2023 12:48:15 -0800 (PST) X-Virus-Scanned: amavisd-new at ewheeler.net Received: from mx.ewheeler.net ([127.0.0.1]) by localhost (mx.ewheeler.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id or6Ztqgsdytl; Thu, 2 Feb 2023 12:48:11 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx.ewheeler.net (Postfix) with ESMTPSA id 8457246; Thu, 2 Feb 2023 12:48:11 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 mx.ewheeler.net 8457246 Date: Thu, 2 Feb 2023 12:48:11 -0800 (PST) From: Eric Wheeler To: Coly Li cc: Andrea Tomassetti , Kent Overstreet , linux-bcache@vger.kernel.org Subject: Re: [RFC] Live resize of backing device In-Reply-To: Message-ID: <3b52d311-9ab5-5fcc-3bb3-cc844caa2eb@ewheeler.net> References: <9474c19e-56f0-cb4d-68c-405c55aef281@ewheeler.net> <4ddb082f-cefc-644e-2ccf-56d41207ecd3@devo.com> <107e8ceb-748e-b296-ae60-c2155d68352d@suse.de> <755CAB25-BC58-4100-A524-6F922E1C13DC@suse.de> <50e64fcd-3bd8-4175-c96e-5fa2ffe051d4@devo.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323328-1719411363-1675370891=:28752" Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-1719411363-1675370891=:28752 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT On Fri, 3 Feb 2023, Coly Li wrote: > > 2023年1月27日 20:44，Andrea Tomassetti 写道： > > From 83f490ec8e81c840bdaf69e66021d661751975f2 Mon Sep 17 00:00:00 2001 > > From: Andrea Tomassetti > > Date: Thu, 8 Sep 2022 09:47:55 +0200 > > Subject: [PATCH v2] bcache: Add support for live resize of backing devices > > > > Signed-off-by: Andrea Tomassetti > > --- > > Hi Coly, > > this is the second version of the patch. As you correctly pointed out, > > I implemented roll-back functionalities in case of error. > > I'm testing this funcionality using QEMU/KVM vm via libvirt. > > Here the steps: > > 1. make-bcache --writeback -B /dev/vdb -C /dev/vdc > > 2. mkfs.xfs /dev/bcache0 > > 3. mount /dev/bcache0 /mnt > > 3. dd if=/dev/random of=/mnt/random0 bs=1M count=1000 > > 4. md5sum /mnt/random0 | tee /mnt/random0.md5 > > 5. [HOST] virsh blockresize --path --size > > 6. xfs_growfs /dev/bcache0 > > 6. Repeat steps 3 and 4 with a different file name (e.g. random1.md5) > > 7. umount/reboot/remount and check that the md5 hashes are correct with > > md5sum -c /mnt/random?.md5 > > [snipped] > > Hi Andrea, > > For the above step 5, could you provide a specific command line for me to reproduce? > > I tried to resize the disk by virsh from 400G to 800G, the disk resize > doesn’t happen online, I have to stop and restart the virtual machine > and see the resized disk. Coly, The `virsh blockresize` command only informs the vm that the size has changed. You will need to resize the disk itself using `lvresize` or whatever your VM's backing device is. If you're backing device for the virtual machine is a file, then you could use `truncate -s /file/path` before issuing `virsh blockresize`. Another possibility: are you using virtio-blk as shown in his example, or a different virtual driver like virtio-scsi? If the VM doesn't detect it you might need to do this if its a virtio-scsi disk on the inside: for i in /sys/class/scsi_host/*/scan; do echo - - - > $i; done If you're using virtio-blk (vda) then it should be immediate. I don't think IDE will work at all, and not sure about nvme. -- Eric Wheeler > Thanks. > > Coly Li > > --8323328-1719411363-1675370891=:28752--