Installation guide

Chapter 28. Miscellaneous storage topics
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4. Mount the loop device which to a directory. If required, create the directory. This example uses /
mnt/guest1 for mounting the partition.
# mkdir /mnt/guest1
# mount /dev/mapper/loop0p1 /mnt/guest1 -o loop,ro
5. The files are now available for reading in the /mnt/guest1 directory. Read or copy the files.
6. Unmount the device so the guest image can be reused by the guest. If the device is mounted the
guest cannot access the image and therefore cannot start.
# umount /mnt/guest1
7. Disconnect the image file from the partition mappings.
# kpartx -d /var/lib/libvirt/images/guest1.img
The guest can now be restarted.
Accessing data from guest LVM volumes
Many Linux guests use Logical Volume Management (LVM) volumes. Additional steps are required to
read data on LVM volumes on virtual storage images.
1. Add the partition mappings for the guest1.img to the recognized devices in the /dev/mapper/
directory.
# kpartx -a /var/lib/libvirt/images/guest1.img
2. In this example the LVM volumes are on a second partition. The volumes require a rescan with
the vgscan command to find the new volume groups.
# vgscan
Reading all physical volumes . This may take a while...
Found volume group "VolGroup00" using metadata type lvm2
3. Activate the volume group on the partition (called VolGroup00 by default) with the vgchange -
ay command.
# vgchange -ay VolGroup00
2 logical volumes in volume group VolGroup00 now active.
4. Use the lvs command to display information about the new volumes. The volume names (the LV
column) are required to mount the volumes.
# lvs
LV VG Attr Lsize Origin Snap% Move Log Copy%
LogVol00 VolGroup00 -wi-a- 5.06G
LogVol01 VolGroup00 -wi-a- 800.00M
5. Mount /dev/VolGroup00/LogVol00 in the /mnt/guestboot/ directory.