From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx2.redhat.com (mx2.redhat.com [10.255.15.25]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id l7RG9Htw030933 for ; Mon, 27 Aug 2007 12:09:17 -0400 Received: from mail2.syneticon.net (mail.syneticon.net [213.239.212.131]) by mx2.redhat.com (8.13.1/8.13.1) with ESMTP id l7RG99oO029194 for ; Mon, 27 Aug 2007 12:09:10 -0400 Received: from postfix1.syneticon.net (postfix1.syneticon.net [192.168.112.6]) by mail2.syneticon.net (Postfix) with ESMTP id 7B4A153BD8 for ; Mon, 27 Aug 2007 18:08:59 +0200 (CEST) Received: from localhost (filter1.syneticon.net [192.168.113.3]) by postfix1.syneticon.net (Postfix) with ESMTP id 3C5E69325 for ; Mon, 27 Aug 2007 18:08:59 +0200 (CEST) Received: from postfix1.syneticon.net ([192.168.113.4]) by localhost (mx03.syneticon.net [192.168.113.3]) (amavisd-new, port 10025) with ESMTP id odtwcaeWhKj8 for ; Mon, 27 Aug 2007 18:08:55 +0200 (CEST) Received: from [192.168.10.145] (xdsl-87-79-96-91.netcologne.de [87.79.96.91]) by postfix1.syneticon.net (Postfix) with ESMTP for ; Mon, 27 Aug 2007 18:08:55 +0200 (CEST) Message-ID: <46D2F715.9000308@wpkg.org> Date: Mon, 27 Aug 2007 18:08:53 +0200 From: Tomasz Chmielewski MIME-Version: 1.0 Subject: Re: [linux-lvm] "cannot allocate memory" when trying to do a snapshot? References: <46CEE6FF.1090000@wpkg.org> In-Reply-To: <46CEE6FF.1090000@wpkg.org> Content-Transfer-Encoding: 7bit Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: LVM general discussion and development Tomasz Chmielewski schrieb: > I have a server with ~1.5T PV, on which I have several logial volumes > (LVs). > > I decided to do a snapshot for five of these LVs, and it succeeded, but > only few times. > > dom-dc1 san1 owi-ao 8.00G > dom-oss1 san1 owi-ao 16.00G > dom-sql1 san1 owi-ao 8.00G > dom-sql1-2 san1 owi-ao 50.00G > dom-ts1 san1 owi-ao 16.00G > > For each of the LVs, I made 5G snapshots. > I could make three snapshots for all of them, but the fourth snapshot > failed for some LVs (in all, I could only make 18 * 5GB snapshots). > > Why? > > I'm using Debian Etch, with its 2.6.18 64 bit kernel. > The machine has 512 MB RAM, and 3 GB swap: Some more info on that. Apparently, this whole snapshotting thing is not very stable, and there are bugs in it. I just played a bit more with creating snapshots. Below, although creating a snapshot fails, a new logical volume is created: # lvcreate -L100G -s -n backup-snapshot /dev/san1/backup File descriptor 3 left open File descriptor 5 left open File descriptor 7 left open device-mapper: reload ioctl failed: Cannot allocate memory Failed to suspend origin backup # lvs File descriptor 3 left open File descriptor 5 left open File descriptor 7 left open LV VG Attr LSize Origin Snap% Move Log Copy% backup san1 -wi-ao 628.28G backup-snapshot san1 -wi-d- 100.00G (...) So, if it fails, at least it shouldn't create any phantom volumes. Does lvm snapshotting work any better with newer kernels? -- Tomasz Chmielewski http://wpkg.org