http://www.fedoraforum.org/forum/archive/index.php/t-64964.html See "Jeff Sadowski" History: I used Fedora's default installer to put F13 on a clean disk after a drive failure. No worries, as I had just checked my backups! The default installer created a logical volume group using LVM2 with each of my partitions as an LV within it. Well, whatever. I spent a few days configuring the system and decided to fetch the backup. I ended up messing up /etc/fstab. No worries still: I've been there before! You just boot from the rescue DVD and move the old /etc/fstab back into place. Booting from the rescue DVD said there were no hard drives: eeesh, this is truly bad. Turns out that whatever filesystem utility F13 rescue CD runs by default does not know about LVM2. You have to start lvm from the rescue shell, run a bunch of commands like "vgchange" and *then* mount the LVG. I can't believe it. Don't ask how many hours it took me to figure this out. And I still can't read my backup disk. Thanks for feeling sorry for me. Problem: booting F13 from rescue disk didn't work because the mounter/scanner on the rescue disk doesn't understand the LVM2 that anaconda uses to create logical volume groups. So I had to use LVM (not dmsetup!) to reconfigure the LVG and LVs so that the mounter would recognize them. What to do: 1. Get into the rescue bash shell. Typing mount -t ext4 /dev/sda2 /mnt/sysimage does not work because /dev/sda2 is not an ext4 filesystem, it's an LV! 2. ls /dev The disk and its partitions (dev/sda, etc.) should appear. lvmdiskscan knows about the LVG but can't seem to use it. The LVG does *not* appear in /dev/mapper. 3. Then modprobe dm-mod lvm [get into LVM; vgchange and vgmknodes not know to bash!] vgchange -ay vgmknodes 4. lvdisplay and vgdisplay now know about the partitions on /dev/sda. 5. Now mount /dev/mapper/ls_root /mnt/sysimage mounts the root filesystem! Whatever problem caused unbootability can now be fixed in the old-fashioned way. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& Tomales: alison@tomales ;-) df Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_tomales-lv_root 98G 14G 83G 14% / tmpfs 2.0G 732K 2.0G 1% /dev/shm /dev/sda3 485M 63M 397M 14% /boot /dev/mapper/vg_tomales-lv_home 301G 28G 259G 10% /home /dev/sdc1 7.6G 18M 7.5G 1% /media/00CC-1182 alison@tomales ;-) mount /dev/mapper/vg_tomales-lv_root on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw) /dev/sda3 on /boot type ext4 (rw) /dev/mapper/vg_tomales-lv_home on /home type ext4 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) gvfs-fuse-daemon on /home/alison/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=alison) /dev/sdc1 on /media/00CC-1182 type vfat (rw,nosuid,nodev,uhelper=udisks,uid=500,gid=500,shortname=mixed,dmask=0077,utf8=1,flush) alison@tomales ;-) sudo lvmdiskscan [sudo] password for alison: /dev/ram0 [ 16.00 MiB] /dev/root [ 98.81 GiB] /dev/ram1 [ 16.00 MiB] /dev/sda1 [ 41.99 GiB] /dev/dm-1 [ 5.88 GiB] /dev/ram2 [ 16.00 MiB] /dev/sda2 [ 13.09 GiB] /dev/dm-2 [ 305.47 GiB] /dev/ram3 [ 16.00 MiB] /dev/sda3 [ 500.00 MiB] /dev/ram4 [ 16.00 MiB] /dev/ram5 [ 16.00 MiB] /dev/sda5 [ 410.19 GiB] LVM physical volume /dev/ram6 [ 16.00 MiB] /dev/ram7 [ 16.00 MiB] /dev/ram8 [ 16.00 MiB] /dev/ram9 [ 16.00 MiB] /dev/ram10 [ 16.00 MiB] /dev/ram11 [ 16.00 MiB] /dev/ram12 [ 16.00 MiB] /dev/ram13 [ 16.00 MiB] /dev/ram14 [ 16.00 MiB] /dev/ram15 [ 16.00 MiB] /dev/sdc1 [ 7.53 GiB] 1 disk 22 partitions 0 LVM physical volume whole disks 1 LVM physical volume alison@tomales ;-) sudo fdisk -l Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xa287a9ef Device Boot Start End Blocks Id System /dev/sda1 1 5482 44032000 7 HPFS/NTFS /dev/sda2 59093 60801 13726720 7 HPFS/NTFS /dev/sda3 * 5482 5546 512000 83 Linux /dev/sda4 5546 59093 430111744 5 Extended /dev/sda5 5546 59093 430110720 8e Linux LVM Partition table entries are not in disk order Disk /dev/dm-0: 106.1 GB, 106099113984 bytes 255 heads, 63 sectors/track, 12899 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-0 doesn't contain a valid partition table Disk /dev/dm-1: 6308 MB, 6308233216 bytes 255 heads, 63 sectors/track, 766 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-1 doesn't contain a valid partition table Disk /dev/dm-2: 328.0 GB, 327994572800 bytes 255 heads, 63 sectors/track, 39876 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-2 doesn't contain a valid partition table Disk /dev/sdc: 8086 MB, 8086618112 bytes 255 heads, 63 sectors/track, 983 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x04dd5721 Device Boot Start End Blocks Id System /dev/sdc1 * 1 984 7897056+ b W95 FAT32 Partition 1 has different physical/logical endings: phys=(982, 254, 63) logical=(983, 36, 13) alison@tomales ;-) &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& bonnet: [alison@bonnet ~]$ df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_bonnet-lv_root 100791728 5541284 94226820 6% / tmpfs 3839496 412 3839084 1% /dev/shm /dev/sda1 495844 46777 423467 10% /boot /dev/mapper/vg_bonnet-lv_home 1264705152 982712 1199479140 1% /home /dev/mapper/vg_bonnet-lv_snapshot 16126920 171056 15136664 2% /snapshot /dev/sdb1 7881644 17816 7863828 1% /media/00CC-1182 [alison@bonnet ~]$ mount /dev/mapper/vg_bonnet-lv_root on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0") /dev/sda1 on /boot type ext4 (rw) /dev/mapper/vg_bonnet-lv_home on /home type ext4 (rw) /dev/mapper/vg_bonnet-lv_snapshot on /snapshot type ext4 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) gvfs-fuse-daemon on /home/alison/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=alison) /dev/sdb1 on /media/00CC-1182 type vfat (rw,nosuid,nodev,uhelper=udisks,uid=500,gid=500,shortname=mixed,dmask=0077,utf8=1,flush) [alison@bonnet ~]$ sudo lvmdiskscan /dev/ram0 [ 16.00 MiB] /dev/root [ 97.66 GiB] /dev/ram1 [ 16.00 MiB] /dev/sda1 [ 500.00 MiB] /dev/dm-1 [ 9.31 GiB] /dev/ram2 [ 16.00 MiB] /dev/sda2 [ 1.32 TiB] LVM physical volume /dev/dm-2 [ 1.20 TiB] /dev/ram3 [ 16.00 MiB] /dev/sda3 [ 48.83 GiB] /dev/dm-3 [ 15.62 GiB] /dev/ram4 [ 16.00 MiB] /dev/ram5 [ 16.00 MiB] /dev/ram6 [ 16.00 MiB] /dev/ram7 [ 16.00 MiB] /dev/ram8 [ 16.00 MiB] /dev/ram9 [ 16.00 MiB] /dev/ram10 [ 16.00 MiB] /dev/ram11 [ 16.00 MiB] /dev/ram12 [ 16.00 MiB] /dev/ram13 [ 16.00 MiB] /dev/ram14 [ 16.00 MiB] /dev/ram15 [ 16.00 MiB] /dev/sdb1 [ 7.53 GiB] 1 disk 22 partitions 0 LVM physical volume whole disks 1 LVM physical volume [alison@bonnet ~]$ sudo fdisk -l Disk /dev/sda: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xa8a8a8a8 Device Boot Start End Blocks Id System /dev/sda1 * 1 64 512000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 64 176028 1413426176 8e Linux LVM /dev/sda3 133675 140049 51198745+ a5 FreeBSD Partition 3 does not end on cylinder boundary. Disk /dev/dm-0: 104.9 GB, 104857600000 bytes 255 heads, 63 sectors/track, 12748 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-0 doesn't contain a valid partition table Disk /dev/dm-1: 9999 MB, 9999220736 bytes 255 heads, 63 sectors/track, 1215 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-1 doesn't contain a valid partition table Disk /dev/dm-2: 1315.7 GB, 1315702833152 bytes 255 heads, 63 sectors/track, 159958 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-2 doesn't contain a valid partition table Disk /dev/dm-3: 16.8 GB, 16777216000 bytes 255 heads, 63 sectors/track, 2039 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-3 doesn't contain a valid partition table Disk /dev/sdb: 8086 MB, 8086618112 bytes 255 heads, 63 sectors/track, 983 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x04dd5721 Device Boot Start End Blocks Id System /dev/sdb1 * 1 984 7897056+ b W95 FAT32 Partition 1 has different physical/logical endings: phys=(982, 254, 63) logical=(983, 36, 13) [alison@bonnet ~]$