From mboxrd@z Thu Jan 1 00:00:00 1970 From: lembark@wrkhors.com Subject: Re: [linux-lvm] extending a logical volume Message-Id: <12230000.1011638456@duke.wrkhors.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: Date: Mon Jan 21 12:43:02 2002 List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-lvm@sistina.com -- Pierrick PONS on 01/21/02 19:09:31 +0100 > I've read the extending logical volume section and I can't believe this. > According to the doc, it would be impossible to extend a logical volume > without unmounting it first. > I'm using a ext3 (with a 2.4.17 kernel) filesystem and I'd like to extend my > logical volume without unmounting it first. This would be used on a > production server, so I can't unmount any logical volume. > > I've seen that a ext2online patch does exist, maybe this fonctionnality is > still implemented in a newer kernel ? > > Could you give me, if it exists, a method to extend the size without unmount > the logical volume ? > > Thank's a lot. Put it another way: You can lvextend a mounted volume. There isn't any good way to extend the file system while it's mounted. Adding the cyl groups to a mounted file system would blow up several parts of the VFS layer. Since extending the LVM takes O(ms) to finish there isn't much gain in doing it mounted anyway. The simplest way to handle it is unmounting, fsck-ing and re-mounting the thing immediately after your weekly backup, when users have to be off the system anyway [if you want to tell me that the system is too important to offline for a backup I'd strongly suggest finding a 9-story window near the console, it'll be easier to handle it yourself than have the users do it for you after a crash looses all of the data]. If the sytsem is used for real-time processing then simply switch to the backup server for 10 minutes, extend and validate the system then switch back. Total time for, say, 100GB file system doubling in size would be 60 seconds on any reasonably fast I/O system, nearly all of which is spent extending the filesystem. Even HP's LVM -- probably the most forgiving of all -- has to be dismounted for extendfs; lvextend can be run any time you like. -- Steven Lembark 2930 W. Palmer Workhorse Computing Chicago, IL 60647 +1 800 762 1582