From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Johnson Subject: Re: Using latest e2fsprogs on various offline VM ext filesystems Date: Sat, 18 Apr 2015 21:30:46 +0100 Message-ID: <5532BEF6.5010801@gmail.com> References: Reply-To: Daniel Johnson Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Andreas Dilger Return-path: Received: from mail-wg0-f48.google.com ([74.125.82.48]:33750 "EHLO mail-wg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752033AbbDRUat (ORCPT ); Sat, 18 Apr 2015 16:30:49 -0400 Received: by wgin8 with SMTP id n8so142961458wgi.0 for ; Sat, 18 Apr 2015 13:30:48 -0700 (PDT) in-reply-to: Sender: linux-ext4-owner@vger.kernel.org List-ID: Great, thanks Andreas for confirming that, and for the snapshot tip. Dan On 18/04/15 16:12, Andreas Dilger wrote: > You can safely use newer e2fsprogs on older file systems. This should not > affect compatibility with older kernels in any way, unless you explicitly > enable features. > > Note that if you are using LVM/DM you could create a snapshot of the > running device and run e2fsck on that. If no errors are found then you > don't need to stop the VM at all. You can reset the last checked counter > and mount count via tune2fs. Only if you find an error in the snapshot do > you need to unmount the filesystem to fix it. > > Cheers, Andreas > >> On Apr 18, 2015, at 06:46, Daniel Johnson wrote: >> >> Apologies if this "user" question has been asked before. >> >> Tomorrow I will be stopping a couple of dozen kvm virtual machines >> running various Linux distros and running a forced e2fsck on all of >> their ext filesystems. The distros are a mix of various flavours of >> Ubuntu, Debian and Centos, so will include some fs created with older >> kernels and E2fsprogs. >> >> The host is 64-bit Centos 6 running vanilla kernel 3.14.39. I figured >> I'll build the latest E2fsprogs 1.42.12 for this rather than using the >> Centos 6 e2fsprogs-1.41.12-21.el6.x86_64. >> >> My question is; should it be safe in theory to use the latest >> E2fsprogs on a mix of ext filesystems in this way? I would have >> thought so but don't want to rely on any assumptions :-) >> >> I'll be setting up device maps on the host server to get to the >> filesystems on each VMs virtual disk, and doing read only checks. But >> if anything needs a repair then I could potentially have a fs modified >> on newer kernel & userspace that then has to boot inside a VM with a >> distro with much older kernel and userspace such as Centos 5, which is >> what I'm concerned about. >> >> Thanks, >> Dan