From owner-freebsd-hackers@FreeBSD.ORG Tue May 31 14:40:40 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8A7A216A41C for ; Tue, 31 May 2005 14:40:40 +0000 (GMT) (envelope-from steve@lonres.com) Received: from anchor-post-36.mail.demon.net (anchor-post-36.mail.demon.net [194.217.242.86]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3748A43D49 for ; Tue, 31 May 2005 14:40:40 +0000 (GMT) (envelope-from steve@lonres.com) Received: from mail.lonres.com ([194.70.153.187]) by anchor-post-36.mail.demon.net with esmtp (Exim 4.42) id 1Dd7v3-000ED3-Km for freebsd-hackers@freebsd.org; Tue, 31 May 2005 14:40:38 +0000 Received: from bibipentium.lonres.com (bibipentium.lonres.com [10.10.10.225]) by mail.lonres.com (Postfix) with SMTP id 559532E09F for ; Tue, 31 May 2005 15:40:37 +0100 (BST) Received: by bibipentium.lonres.com (sSMTP sendmail emulation); Tue, 31 May 2005 15:41:15 +0100 From: "Steve Roome" Date: Tue, 31 May 2005 15:41:15 +0100 To: freebsd-hackers@freebsd.org Message-ID: <20050531144115.GA1317@bibipentium.lonres.com> Mail-Followup-To: Steve Roome , freebsd-hackers@freebsd.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.1i X-Mailman-Approved-At: Wed, 01 Jun 2005 12:01:01 +0000 Subject: Snapshots mtime seems to be getting updated X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 May 2005 14:40:40 -0000 Hi posted this to -questions, but I'm not getting any takers. This is on a few variants on -stable up to and around 5.4. I've not tested this on any FreeBSD box yet and found things to be working as expected. ------------------------------------------------------------------------ I'm taking a snapshot of a filesystem, mdconfigging and then mounting it read only,noatime. Somehow the mtime on the snapshot file is being updated (I think it's when I read) from the newly mounted md device of the snapshot. This doesn't seem right, and I've included the script I'm using to do this. I'm not really interested in ways to fix this script, though there are probably many better ways to do this, right now I'm just unsure if this is the correct behavious for snapshots. Thanks in advance if anyone knows what's going on here, Steve Roome P.S. I'm not subscribed to the mailing list, please cc responses to me. dodgy snapshot/remount/tar up script. ------------------------------------------------------------------------ #!/bin/sh # Copyright Steve Roome. You can do what you like with this code, I'd # suggest that you delete it. If you want to run it use: # ./whateverthisis.sh SNAPMOUNT="/backup_mnt" die() { echo $* exit 1 } MOUNT=$1 MYUID=`id -u` [ $MYUID -eq "0" ] || die "You are not root, you will need to be root to mount the snapshot" # Check that this is a UFS2 mount point /sbin/mount -p -t ufs | /usr/bin/awk '{print $2}' | grep -cx ${MOUNT} 2>&1 >/dev/null || die "$MOUNT is not a mounted ufs filesystem" BACKUP_DIR=${MOUNT}/hourly_snaps # Check that BACKUP_DIR exists and is writable SNAPDIR=$MOUNT/.snap [ -d $SNAPDIR ] || mkdir $SNAPDIR || die "Can't create $SNAPDIR" SNAPBASE=${SNAPDIR}/`/bin/date "+%Y.%m.%d.%H:%M"` SNAPFILE=${SNAPBASE}.snap SNAPMOUNT="/backup_mnt" SNAPTGZ=${SNAPBASE}.tgz TEMPTGZ=${SNAPBASE}.temp START_PWD=`pwd` #echo "Snapshots will be saved in ${SNAPDIR}" #echo "The next snapshot will be named ${SNAPFILE}" #echo "The snapshot will be mounted on ${SNAPMOUNT}" #echo "${SNAPMOUNT} will be tgz'ed to ${SNAPTGZ}" touch ${SNAPFILE} > /dev/null 2>&1 && rm ${SNAPFILE} || die "Can't save snapshot in $SNAPFILE" touch ${TEMPTGZ} > /dev/null 2>&1 && rm ${TEMPTGZ} || die "Can't save snapshot in $SNAPFILE" [ -d $SNAPMOUNT ] || mkdir $SNAPMOUNT || die "Can't create mount point $SNAPMOUNT" # Check that SNAPFILE can be created/deleted mksnap_ffs $MOUNT $SNAPFILE && MD_DEV=`mdconfig -a -t vnode -f $SNAPFILE` && mount -o ro,noatime /dev/$MD_DEV /${SNAPMOUNT} cd ${SNAPMOUNT} && tar -czp --exclude .snap/ -f ${TEMPTGZ} . 2>/dev/null || die "Failed to create tarfile: ${TEMPTGZ} PLEASE INVESTIGATE" cd ${START_PWD} umount ${SNAPMOUNT} MD_UNIT=`echo $MD_DEV | sed -e 's/^md//g'` mdconfig -d -u ${MD_UNIT} && rm -f ${SNAPFILE} && rmdir ${SNAPMOUNT} && mv ${TEMPTGZ} ${SNAPTGZ} && echo "${SNAPTGZ} ceated successfully from snapshot of ${MOUNT}" || die "Did not manage to clear up after backing up ${MOUNT}\nIntervention recommended" # finished okay! exit 0