From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 17 Apr 2001 22:08:04 +0200 Message-ID: <20010417220804.T31343@engen.priv.no> Mime-Version: 1.0 Content-Disposition: inline From: Vegard Engen Subject: [linux-lvm] Strangenesses with snapshots, 0.9.1-beta6. 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: List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-lvm@sistina.com Hello, The two last days I started testing 0.9.1-beta6 for my home-machine, hoping to get rid of the everlasting partitioning pain. Trying out the snapshots, I get worrying errors when making a full backup of my ~4 GB /home partition. This is a pretty long mail demonstrating the error.... I'm using kernel 2.4.3, with ext2 filesystems on the logical volumes. The kernel is patched with LVM 0.9.1-beta6 patches, and these patches succeeded. I followed the instructions and made a lvm-0.9.1_beta6-2.4.3.patch - which applied flawlessly to the kernel. I have made the following backup-script as a test: ----- snip ------ #!/bin/sh if [ -e /dev/backup/home ] ; then umount /dev/backup/home; lvremove -f /dev/backup/home; fi if [ -e /dev/vg/backup ] ; then umount /dev/vg/backup lvremove -f /dev/vg/backup fi lvcreate -L 1000M -s -n backup /dev/vg/nhome mount /dev/vg/backup /mnt/backup lvcreate -L 5000M -n home backup mount /dev/backup/home /mnt/bhome cp -a /mnt/backup/* /mnt/bhome ----- snip ------ I tried it out. There was very little activity at all on the system when running this, so filling up the snapshot-volume is not an issue here. Well, the following is output from the script. This is a little long - I'm commenting inside the output, so please read.... middagspynten:/usr/local/sbin# ./backup_home.sh lvcreate lvcreate -- WARNING: the snapshot must be disabled if it gets full lvcreate -- INFO: using default snapshot chunk size of 64 KB for "/dev/vg/backup" lvcreate -- doing automatic backup of "vg" lvcreate -- logical volume "/dev/vg/backup" successfully created mount: block device /dev/vg/backup is write-protected, mounting read-only lvcreate lvcreate -- doing automatic backup of "backup" lvcreate -- logical volume "/dev/backup/home" successfully created [*** these are normal files and are indeed readable in the normal /home ***] cp: `/mnt/backup/vegard/Mail/irc/ircd-users/356' has unknown file type cp: `/mnt/backup/vegard/Mail/cups/343' has unknown file type cp: `/mnt/backup/vegard/Mail/cups/344' has unknown file type cp: `/mnt/backup/vegard/Mail/cups/346' has unknown file type [ *** some debug *** ] This works: middagspynten:/home/vegard/Mail/irc/ircd-users# cat 356 This is quite strange: middagspynten:/mnt/backup/vegard/Mail/irc/ircd-users# ls -l 356 ?--sr-srw- 15370 1734492719 1868774980 4482544195540565054 Feb 17 2003 356 middagspynten:/mnt/backup/vegard/Mail/irc/ircd-users# cat 356 cat: 356: Invalid argument [ *** End debug, continue log *** ] cp: cannot stat `/mnt/backup/vegard/Mail/unix/openldap-general/314': Input/output error cp: cannot stat `/mnt/backup/vegard/Mail/unix/openldap-general/315': Input/output error cp: cannot stat `/mnt/backup/vegard/Mail/unix/openldap-general/316': Input/output error cp: cannot stat `/mnt/backup/vegard/Mail/unix/openldap-general/317': Input/output error [ *** This is another strangeness *** ] middagspynten:/mnt/backup/vegard/Mail/unix/openldap-general# ls -l ..... -rw------- 1 vegard vegard 3454 Dec 11 1999 309 -rw------- 1 vegard vegard 4530 Sep 9 1999 31 -rw------- 1 vegard vegard 4147 Dec 11 1999 310 -rw------- 1 vegard vegard 3294 Dec 11 1999 311 -rw------- 1 vegard vegard 3452 Dec 11 1999 312 -rw------- 1 vegard vegard 5775 Dec 13 1999 313 -rw------- 1 vegard vegard 3292 Dec 22 1999 318 -rw------- 1 vegard vegard 4318 Dec 22 1999 319 -rw------- 1 vegard vegard 4384 Sep 11 1999 32 ..... middagspynten:/mnt/backup/vegard/Mail/unix/openldap-general# cat 314 314: Input/output error This works: middagspynten:/mnt/backup/vegard/Mail/unix/openldap-general# cat 318 [ *** These are the same as the first one *** ] cp: `/mnt/backup/vegard/Mail/inbox/234' has unknown file type cp: `/mnt/backup/vegard/Mail/inbox/235' has unknown file type cp: `/mnt/backup/vegard/Mail/inbox/236' has unknown file type cp: `/mnt/backup/vegard/Mail/inbox/237' has unknown file type [ *** This *is* actually an error in my .procmailrc and the name of the directory ;-) - the \255 is actually an \xad, though, so it's not an \255. But, apart from that, it's exactly like the second case *** ] cp: cannot stat `/mnt/backup/vegard/Mail/linux/tecra\255linux/233': Input/output error cp: cannot stat `/mnt/backup/vegard/Mail/linux/tecra\255linux/234': Input/output error cp: cannot stat `/mnt/backup/vegard/Mail/linux/tecra\255linux/235': Input/output error cp: cannot stat `/mnt/backup/vegard/Mail/linux/tecra\255linux/236': Input/output error [ *** This is a third strangeness - and more worrying for me, because this time, it *works* in the snapshot volume, but gets corrupted on the copy *** ] cp: cannot create regular file `/mnt/bhome/vegard/Mail/linux/linux-net/357': No such device or address cp: cannot create regular file `/mnt/bhome/vegard/Mail/linux/linux-net/358': No such device or address cp: cannot create regular file `/mnt/bhome/vegard/Mail/linux/linux-net/359': No such device or address cp: cannot create regular file `/mnt/bhome/vegard/Mail/linux/linux-net/360': No such device or address [ **** Debugging on the above problem **** ] middagspynten:/mnt/backup/vegard/Mail/linux/linux-net# ls -l 359 -rw------- 1 vegard vegard 5351 Dec 6 1999 359 This file is also cat'able. But: middagspynten:/mnt/bhome/vegard/Mail/linux/linux-net# ls -l 359 s-wx------ 1 3233857728 3233857728 0 May 17 1936 359 middagspynten:/mnt/bhome/vegard/Mail/linux/linux-net# cat 359 cat: 359: No such device or address [ *** Here, I don't know what happened. Thie is a workable file on /mnt/backup, but in /mnt/bhome it turns into a directory, which it later tries to overwrite *** ] cp: cannot overwrite directory `/mnt/bhome/vegard/Mail/linux/linux-usb/111' with non-directory [ *** The rest is cases described before *** ] This is looks like pretty serious bugs to me. This seemed only to happen down in my MH-directories. For those who doesn't know, MH is a mailfolder system which stores each mail in one file, which it names according to the message number in the folder. However, the MH-directory compromises quite a lot of my home-directory, too, I think I counted it to ~ 80.000 files, last I counted. Statistically, it's still strange that it shouldn't happen in the rest of my /home partition, as the rest isn't exactly insignificant either. So I *think* it must be somehow related to MH or how MH folders look like. Perhaps something with the size of directories, or the number of levels in the directory hierarchy. But this is only guesswork. It does, however, seem to work on the real /home, I've not yet discovered any errors here. - Vegard