Never seen this here. Did a quick test and it works with 1.0.7 on 2.4.21 vanilla here. It could be a problem with that RedHat kernel. Regards, Heinz -- The LVM Guy -- On Tue, Sep 23, 2003 at 05:14:31PM -0400, Montgomery, Kendal L wrote: > I've seen a few things about using lvm on a loopback filesystem, but nothing > concrete, so I tried it myself. Most everything works okay until I get to > acutally mounting the filesystem. Here are the steps I did: > > [root@klmontg tmp]# dd if=/dev/zero of=fake_disk.img bs=1M count=500 > 500+0 records in > 500+0 records out > [root@klmontg tmp]# losetup /dev/loop0 fake_disk.img > [root@klmontg tmp]# pvcreate /dev/loop0 > pvcreate -- physical volume "/dev/loop0" successfully created > > [root@klmontg tmp]# vgcreate /dev/vgtest /dev/loop0 > vgcreate -- INFO: using default physical extent size 4 MB > vgcreate -- INFO: maximum logical volume size is 255.99 Gigabyte > vgcreate -- doing automatic backup of volume group "vgtest" > vgcreate -- volume group "vgtest" successfully created and activated > > [root@klmontg tmp]# lvcreate --name lv_one --size 200M /dev/vgtest > lvcreate -- doing automatic backup of "vgtest" > lvcreate -- logical volume "/dev/vgtest/lv_one" successfully created > > [root@klmontg tmp]# mke2fs /dev/vgtest/lv_one > mke2fs 1.32 (09-Nov-2002) > Filesystem label= > OS type: Linux > Block size=1024 (log=0) > Fragment size=1024 (log=0) > 51200 inodes, 204800 blocks > 10240 blocks (5.00%) reserved for the super user > First data block=1 > 25 block groups > 8192 blocks per group, 8192 fragments per group > 2048 inodes per group > Superblock backups stored on blocks: > 8193, 24577, 40961, 57345, 73729 > > Writing inode tables: done > Writing superblocks and filesystem accounting information: done > > This filesystem will be automatically checked every 26 mounts or > 180 days, whichever comes first. Use tune2fs -c or -i to override. > [root@klmontg tmp]# e2fsck /dev/vgtest/lv_one > e2fsck 1.32 (09-Nov-2002) > Couldn't find ext2 superblock, trying backup blocks... > e2fsck: Bad magic number in super-block while trying to open > /dev/vgtest/lv_one > > The superblock could not be read or does not describe a correct ext2 > filesystem. If the device is valid and it really contains an ext2 > filesystem (and not swap or ufs or something else), then the superblock > is corrupt, and you might try running e2fsck with an alternate superblock: > e2fsck -b 8193 <device> > > [root@klmontg tmp]# e2fsck -b 8193 /dev/vgtest/lv_one > e2fsck 1.32 (09-Nov-2002) > e2fsck: Bad magic number in super-block while trying to open > /dev/vgtest/lv_one > > The superblock could not be read or does not describe a correct ext2 > filesystem. If the device is valid and it really contains an ext2 > filesystem (and not swap or ufs or something else), then the superblock > is corrupt, and you might try running e2fsck with an alternate superblock: > e2fsck -b 8193 <device> > > [root@klmontg tmp]# mount /dev/vgtest/lv_one /mnt > mount: you must specify the filesystem type > [root@klmontg tmp]# mount -t ext2 /dev/vgtest/lv_one /mnt > mount: wrong fs type, bad option, bad superblock on /dev/vgtest/lv_one, > or too many mounted file systems > > As you can see, one the filesystem was made, nothing else works. I can't > fsck the filesystem on the new logical volume, or mount it. This is > obviously a problem since, well, it's useless unless I can mount it. > > I'm using RedHat 9 with the 2.4.20-20.9 kernel. I've also tried this on > RedHat 8 on another box. I got the latest version of util-linux which is > 2.11z and compiled that (in case it was a possible bug in mount 2.11y which > comes with redhat). I'm using lvm 1.0.3-12 that comes with redhat 9. I > have not tried getting the latest lvm tools. That's my next step... > > Anyone else had this problem, or tried doing this? The reason I wanted to > do this in the first place is so I can test snapshots. I want to be able to > have a filesystem which is static, that I will then take a snapshot of, then > change things on it, and then use the snapshot to bring it back to it's > original form. I know there is some work on union filesystems or > translucent filesystems, and such things, but none of it seems mature > enough, so this solution seemed like it might work until I hit this snag. > > Is anyone else doing this (lvm on loopback)? Does anyone have it working > correctly? Am I doing something wrong? Do I need a different version of > something? > > Thanks in advance for any help. > > Kendal. > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ *** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them *** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Sistina Software Inc. Senior Consultant/Developer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@Sistina.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
