Subject: Re: fsck in background? - msg#00001

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Re: 2.4.x + LBD + LVM?

On Thu, 2003-03-27 at 16:39, Dale J. Stephenson wrote: > > On Thursday, March 27, 2003, at 12:22 PM, Eric Sandeen wrote: > > > On Thu, 27 Mar 2003, Dale J. Stephenson wrote: > > > >> I'm interested in this, but I haven't tried to do it yet. I'd be glad > >> to take a look. Are you applying the 2.4.20-lbd-1.patch to XFS's cvs > >> head, or something else? Ok, 2.4.20-lbd-1.patch does have the b_rsector change now, and XFS cvs has the right code in it if you #define HAVE_SECTOR_T - I submitted a patch to Peter to do this in his patch, btw. So in short, 2.4.20-lbd-1.patch + xfs cvs should be a good combination. > If you could send me a patch that works for xfs/fs, I can try to get it > working with LVM here. My usual test machine has root on a RAID1--do > you know if LBD breaks RAID 1/5 outright, or just for RAID 1/5 > using/making a large block device? I still need to test raid... > I think it's doable, but it won't work without changing the tools. Yikes. Well, a first step would be to ensure that LVM + LBD doesn't break below 2T, I guess. -Eric -- Eric Sandeen XFS for Linux http://oss.sgi.com/projects/xfs sandeen@xxxxxxx SGI, Inc. 651-683-3102

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Re: fsck in background?

Andreas Dilger wrote: On Mar 31, 2003 21:14 +0400, Hans Reiser wrote: Oleg Drokin wrote: On Mon, Mar 31, 2003 at 12:30:37PM +0200, myciel wrote: so I'm curious if maybe fscking in background is planned? - idea is not new and bsd guys say that they have it for freebsd 5.0 in ffs. This is not possible for reiserfs, I think. reiserfs have non-constant metadata location , so while you can certainly check fs consistency of some snapshot, you cannot fix it because all the real data might have ben shifted to other blocks, old blocks might have been already freed and so on. It can be done, but I don't have the funding/staff for it. I wrote a script to do this once, using LVM snapshots. Attached here. I haven't used it in a long time, and didn't do much other than write it and test it out a bit, but it likely works OK. It obviously doesn't actually fix any problems that it detects, but for systems that run a long time it avoids the need to do a shutdown to verify large filesystems are intact. For ext2/3 it also resets the "last checked" count/time so that ext3 will not do gratuitous full fscks if the system has been up over 6 months (assuming you run the script periodically while the system is running). Cheers, Andreas ============================= lvm-fsck ============================= #!/bin/sh # Automatically checks ext2/ext3 filesystems that are currently mounted # and also residing on LVM logical volumes, so that we can snapshot them. # You need to have the LVM VFS locking patch applied for this to work. # # (C) Andreas Dilger, 2001 # # Licensed under the GNU General Public License, version 2 or later #set -vx # Use the PATH to find any installed fsck programs PATH=$PATH:/sbin:/usr/sbin:/usr/local/sbin PROG=`basename $0` FSCKLV=lvfsck lvscan | grep ACTIVE | while read LVSCAN DASH ACTIVE LV LV2 SIZE; do [ "$LV" = "Snapshot" ] && continue if [ "$LV" = "Original" ]; then LV=`echo $LV2 | tr -d \"` else LV=`echo $LV | tr -d \"` fi VG="`dirname $LV`" LVS="$VG/$FSCKLV" # This could be smarter (i.e. removing old snapshot after checking if # another lvm-fsck is running, but we don't want to do concurrent fscks # if it takes a really long time to run, or if the script has problems. # Sadly, lvdisplay does not return an error code if $LVS doesn't exist if [ "`lvdisplay $LVS 2> /dev/null`" ]; then echo "$LVS exists! Unable to check $LV" continue fi # Check if this LV is mounted and has a fsck-able filesystem on it AWKLV="`echo $LV | tr / .`" FSTYPE=`mount | awk "/^$AWKLV/ { print \\$5 }"` FSCK="`which fsck.$FSTYPE 2> /dev/null`" [ "$FSCK" ] || continue echo "$PROG: running read-only $FSCK on $LV" # Just a guess at how much snapshot space we need SIZE="`df -P $LV | tail +2 | awk '{ print $2 / 500 }'`" lvcreate -s -L ${SIZE}k -n $FSCKLV $LV > /dev/null rc=$? if [ $rc -ne 0 ]; then echo "Creating snapshot of $LV at $LVS failed with rc=$rc" 1>&2 continue fi case $FSTYPE in ext2|ext3) $FSCK -f -n $LVS; rc=$? if [ $rc -eq 0 ]; then tune2fs -C 0 $LV > /dev/null tune2fs -T now $LV > /dev/null 2>&1 ;; reiserfs) echo Yes | $FSCK --check $LVS; rc=$? ;; *) echo "Don't know how to check $FSTYPE filesystems passively"; rc=$1;; esac [ $rc -ne 0 ] && echo "$FSCK of $LV failed with rc=$rc" 1>&2 lvremove -f $LVS > /dev/null rc=$? [ $rc -ne 0 ] && echo "lvremove of $LVS failed with rc=$rc" 1>&2 done -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/ Oleg, consider putting a link to this on our web site..... -- Hans

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Re: 2.4.x + LBD + LVM?

On Thu, 2003-03-27 at 16:39, Dale J. Stephenson wrote: > > On Thursday, March 27, 2003, at 12:22 PM, Eric Sandeen wrote: > > > On Thu, 27 Mar 2003, Dale J. Stephenson wrote: > > > >> I'm interested in this, but I haven't tried to do it yet. I'd be glad > >> to take a look. Are you applying the 2.4.20-lbd-1.patch to XFS's cvs > >> head, or something else? Ok, 2.4.20-lbd-1.patch does have the b_rsector change now, and XFS cvs has the right code in it if you #define HAVE_SECTOR_T - I submitted a patch to Peter to do this in his patch, btw. So in short, 2.4.20-lbd-1.patch + xfs cvs should be a good combination. > If you could send me a patch that works for xfs/fs, I can try to get it > working with LVM here. My usual test machine has root on a RAID1--do > you know if LBD breaks RAID 1/5 outright, or just for RAID 1/5 > using/making a large block device? I still need to test raid... > I think it's doable, but it won't work without changing the tools. Yikes. Well, a first step would be to ensure that LVM + LBD doesn't break below 2T, I guess. -Eric -- Eric Sandeen XFS for Linux http://oss.sgi.com/projects/xfs sandeen@xxxxxxx SGI, Inc. 651-683-3102

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Re: fsck in background?

Andreas Dilger wrote: On Mar 31, 2003 21:14 +0400, Hans Reiser wrote: Oleg Drokin wrote: On Mon, Mar 31, 2003 at 12:30:37PM +0200, myciel wrote: so I'm curious if maybe fscking in background is planned? - idea is not new and bsd guys say that they have it for freebsd 5.0 in ffs. This is not possible for reiserfs, I think. reiserfs have non-constant metadata location , so while you can certainly check fs consistency of some snapshot, you cannot fix it because all the real data might have ben shifted to other blocks, old blocks might have been already freed and so on. It can be done, but I don't have the funding/staff for it. I wrote a script to do this once, using LVM snapshots. Attached here. I haven't used it in a long time, and didn't do much other than write it and test it out a bit, but it likely works OK. It obviously doesn't actually fix any problems that it detects, but for systems that run a long time it avoids the need to do a shutdown to verify large filesystems are intact. For ext2/3 it also resets the "last checked" count/time so that ext3 will not do gratuitous full fscks if the system has been up over 6 months (assuming you run the script periodically while the system is running). Cheers, Andreas ============================= lvm-fsck ============================= #!/bin/sh # Automatically checks ext2/ext3 filesystems that are currently mounted # and also residing on LVM logical volumes, so that we can snapshot them. # You need to have the LVM VFS locking patch applied for this to work. # # (C) Andreas Dilger, 2001 # # Licensed under the GNU General Public License, version 2 or later #set -vx # Use the PATH to find any installed fsck programs PATH=$PATH:/sbin:/usr/sbin:/usr/local/sbin PROG=`basename $0` FSCKLV=lvfsck lvscan | grep ACTIVE | while read LVSCAN DASH ACTIVE LV LV2 SIZE; do [ "$LV" = "Snapshot" ] && continue if [ "$LV" = "Original" ]; then LV=`echo $LV2 | tr -d \"` else LV=`echo $LV | tr -d \"` fi VG="`dirname $LV`" LVS="$VG/$FSCKLV" # This could be smarter (i.e. removing old snapshot after checking if # another lvm-fsck is running, but we don't want to do concurrent fscks # if it takes a really long time to run, or if the script has problems. # Sadly, lvdisplay does not return an error code if $LVS doesn't exist if [ "`lvdisplay $LVS 2> /dev/null`" ]; then echo "$LVS exists! Unable to check $LV" continue fi # Check if this LV is mounted and has a fsck-able filesystem on it AWKLV="`echo $LV | tr / .`" FSTYPE=`mount | awk "/^$AWKLV/ { print \\$5 }"` FSCK="`which fsck.$FSTYPE 2> /dev/null`" [ "$FSCK" ] || continue echo "$PROG: running read-only $FSCK on $LV" # Just a guess at how much snapshot space we need SIZE="`df -P $LV | tail +2 | awk '{ print $2 / 500 }'`" lvcreate -s -L ${SIZE}k -n $FSCKLV $LV > /dev/null rc=$? if [ $rc -ne 0 ]; then echo "Creating snapshot of $LV at $LVS failed with rc=$rc" 1>&2 continue fi case $FSTYPE in ext2|ext3) $FSCK -f -n $LVS; rc=$? if [ $rc -eq 0 ]; then tune2fs -C 0 $LV > /dev/null tune2fs -T now $LV > /dev/null 2>&1 ;; reiserfs) echo Yes | $FSCK --check $LVS; rc=$? ;; *) echo "Don't know how to check $FSTYPE filesystems passively"; rc=$1;; esac [ $rc -ne 0 ] && echo "$FSCK of $LV failed with rc=$rc" 1>&2 lvremove -f $LVS > /dev/null rc=$? [ $rc -ne 0 ] && echo "lvremove of $LVS failed with rc=$rc" 1>&2 done -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/ Oleg, consider putting a link to this on our web site..... -- Hans