如果是非lvm格式的，則非常方便，給mount命令傳遞offset引數即可，例如：
[[email protected] xen-images]# fdisk -lu centos_vm1
last_lba(): I don't know how to handle files with mode 81ed
You must set cylinders.
You can do this from the extra functions menu.

Disk centos_vm1: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes

      Device Boot      Start         End      Blocks   Id  System
centos_vm1p1   *          63      208844      104391   83  Linux
centos_vm1p2          208845     4192964     1992060   8e  Linux LVM
看到第一個磁碟分割槽是Linux分割槽，起始於63扇區，直接mount：
[

[email protected] xen-images]# mkdir -p /mnt/disk
[[email protected] xen-images]# mount -o loop,offset=$[63*512] centos_vm1 /mnt/disk/
[[email protected] xen-images]# ls /mnt/disk/
config-2.6.18-92.el5xen      lost+found                   System.map-2.6.18-92.el5xen  xen-syms-2.6.18-92.el5
grub                         message                      vmlinuz-2.6.18-92.el5xen
initrd-2.6.18-92.el5xen.img  symvers-2.6.18-92.el5xen.gz  xen.gz-2.6.18-92.el5
顯示，這個linux分割槽是/boot，root檔案系統在centos_vm1p2的這塊lvm區中，要設法把它mount上來，使用以下方法：

首先找到它的起始偏移，使用fdisk的-u引數在列出磁碟分割槽的時候以扇區(sector)為單位，否則是以柱面(cylinder)為單位的：
[[email protected] xen-images]# fdisk -lu centos_vm1
last_lba(): I don't know how to handle files with mode 81ed
You must set cylinders.
You can do this from the extra functions menu.

Disk centos_vm1: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes

      Device Boot      Start         End      Blocks   Id  System
centos_vm1p1   *          63      208844      104391   83  Linux
centos_vm1p2          208845     4192964     1992060   8e  Linux LVM

從上看出lvm分割槽起始於208845扇區，把這個地址處的分割槽mount為loop裝置：
-f引數表示自動尋找可用的loop裝置檔案，-o指定偏移量。
[[email protected] xen-images]# losetup -f -o $[208845*512] centos_vm1
[[email protected] xen-images]# losetup -a
/dev/loop0: [0806]:1097730 (centos_vm1), offset 106928640

掃描lvm volumns:
[[email protected] xen-images]# lvm pvscan
  PV /dev/loop0   VG VolGroup00   lvm2 [1.88 GB / 0    free]
  Total: 1 [1.88 GB] / in use: 1 [1.88 GB] / in no VG: 0 [0   ]

啟用lvm volumn:
[[email protected] xen-images]# lvm vgchange -ay
  2 logical volume(s) in volume group "VolGroup00" now active
[[email protected] xen-images]# ls /dev/mapper/
control  VolGroup00-LogVol00  VolGroup00-LogVol01
[[email protected] xen-images]# lvm lvs
  LV       VG         Attr   LSize   Origin Snap%  Move Log Copy%  Convert
  LogVol00 VolGroup00 -wi-a-   1.50G                                     
  LogVol01 VolGroup00 -wi-a- 384.00M                            

使用：      
[[email protected] xen-images]# mount /dev/mapper/VolGroup00-LogVol00 /mnt/usb
[[email protected] xen-images]# ls /mnt/usb
bin   dev  home  lost+found  misc  opt       proc  sbin     srv  tmp  var
boot  etc  lib   media       mnt   poweroff  root  selinux  sys  usr

最後，在操作完以後，umount這個裝置，然後設定這個lvm volumn為非活動狀態：
[[email protected] xen-images]# umount /mnt/usb
[[email protected] xen-images]# lvm vgchange -an
  0 logical volume(s) in volume group "VolGroup00" now active
[[email protected] xen-images]# losetup -a
/dev/loop0: [0806]:1097730 (centos_vm1), offset 106928640
[[email protected] xen-images]# losetup -d /dev/loop0