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如何挂载一个镜像文件(how to mount an image file)
08/16/2012master 4 Comments 在使用KVM或Xen虚拟化的情况下,经常需要使用镜像文件(image file),我们可以将Guest系统启动起来,然后对镜像文件进行修改,不过这样有时也是比较麻烦,其实也是可以将镜像文件直接进行mount的,可以用如下两种办法。
(本文写的RAW格式镜像文件的挂载;我的另一篇文章写了“如何挂载qcow2格式的镜像文件”)
方法一:找出分区开始的开始位置,使用mount命令的offset参数偏移掉前面不需要的,即可得到真正的分区。其具体步骤如下:
1. 用“fdisk -lu my.img”查询image信息;
2. 计算image内分区开始的地方(计算offset),用从N号sector(扇区)开始,则offset=N*M (M为一个sector的大小,一般为512)
3. 使用mount命令挂载为loop设备即可。 (如LVM分区,则会较复杂,请见本文最后的介绍)
在Linux系统上具体操作演示如下:
[iyunv@jay-linux image]# fdisk -lu rhel6u2.imgYou must set cylinders.You can do this from the extra functions menu.Disk rhel6u2.img: 0 MB, 0 bytes255 heads, 63 sectors/track, 0 cylinders, total 0 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x00048b34Device Boot Start End Blocks Id Systemrhel6u2.img1 * 2048 1026047 512000 83 LinuxPartition 1 does not end on cylinder boundary.rhel6u2.img2 1026048 104857599 51915776 8e Linux LVMPartition 2 has different physical/logical endings:phys=(1023, 254, 63) logical=(6527, 21, 22)[iyunv@jay-linux image]# echo $((2048*512))1048576[iyunv@jay-linux image]# mount -o loop,offset=1048576 rhel6u2.img /media/[iyunv@jay-linux image]# cd /media/[iyunv@jay-linux media]# lsconfig-2.6.32-220.el6.x86_64 initramfs-3.5.0.img System.map-2.6.32-279.el6.x86_64config-2.6.32-279.el6.x86_64 lost+found System.map-3.5.0efi symvers-2.6.32-220.el6.x86_64.gz vmlinuzgrub symvers-2.6.32-279.el6.x86_64.gz vmlinuz-2.6.32-220.el6.x86_64initramfs-2.6.32-220.el6.x86_64.img System.map vmlinuz-2.6.32-279.el6.x86_64initramfs-2.6.32-279.el6.x86_64.img System.map-2.6.32-220.el6.x86_64 vmlinuz-3.5.0[iyunv@jay-linux media]# echo $((1026048*512))525336576[iyunv@jay-linux media]# umount /media[iyunv@jay-linux media]# cd /home/image/[iyunv@jay-linux image]# umount /media[iyunv@jay-linux image]# mount -o loop,offset=525336576 rhel6u2.img /media/mount: unknown filesystem type 'LVM2_member'(镜像文件中的LVM分区mount的问题,本文最后单独说明)[iyunv@jay-linux image]# fdisk -lu sles11sp2-i386.imgYou must set cylinders.You can do this from the extra functions menu.Disk sles11sp2-i386.img: 0 MB, 0 bytes255 heads, 63 sectors/track, 0 cylinders, total 0 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x0002d3beDevice Boot Start End Blocks Id Systemsles11sp2-i386.img1 2048 4208639 2103296 82 Linux swap / SolarisPartition 1 does not end on cylinder boundary.sles11sp2-i386.img2 * 4208640 41943039 18867200 83 LinuxPartition 2 has different physical/logical endings:phys=(1023, 254, 63) logical=(2610, 212, 34)[iyunv@jay-linux image]# echo $((4208640*512))2154823680[iyunv@jay-linux image]# mount -o loop,offset=2154823680 sles11sp2-i386.img /media[iyunv@jay-linux image]# cd /media/[iyunv@jay-linux media]# lsbin dev home lost+found mnt proc sbin srv sys usrboot etc lib media opt root selinux success tmp var[iyunv@jay-linux image]# umount /media/
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[iyunv@jay-linux image]# fdisk -lu rhel6u2.img
You must set cylinders.
You can do this from the extra functions menu.
Disk rhel6u2.img: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00048b34
Device Boot Start End Blocks Id System
rhel6u2.img1 * 2048 1026047 512000 83 Linux
Partition 1 does not end on cylinder boundary.
rhel6u2.img2 1026048 104857599 51915776 8e Linux LVM
Partition 2 has different physical/logical endings:
phys=(1023, 254, 63) logical=(6527, 21, 22)
[iyunv@jay-linux image]# echo $((2048*512))
1048576
[iyunv@jay-linux image]# mount -o loop,offset=1048576 rhel6u2.img /media/
[iyunv@jay-linux image]# cd /media/
[iyunv@jay-linux media]# ls
config-2.6.32-220.el6.x86_64 initramfs-3.5.0.img System.map-2.6.32-279.el6.x86_64
config-2.6.32-279.el6.x86_64 lost+found System.map-3.5.0
efi symvers-2.6.32-220.el6.x86_64.gz vmlinuz
grub symvers-2.6.32-279.el6.x86_64.gz vmlinuz-2.6.32-220.el6.x86_64
initramfs-2.6.32-220.el6.x86_64.img System.map vmlinuz-2.6.32-279.el6.x86_64
initramfs-2.6.32-279.el6.x86_64.img System.map-2.6.32-220.el6.x86_64 vmlinuz-3.5.0
[iyunv@jay-linux media]# echo $((1026048*512))
525336576
[iyunv@jay-linux media]# umount /media
[iyunv@jay-linux media]# cd /home/image/
[iyunv@jay-linux image]# umount /media
[iyunv@jay-linux image]# mount -o loop,offset=525336576 rhel6u2.img /media/
mount: unknown filesystem type 'LVM2_member'
(镜像文件中的LVM分区mount的问题,本文最后单独说明)
[iyunv@jay-linux image]# fdisk -lu sles11sp2-i386.img
You must set cylinders.
You can do this from the extra functions menu.
Disk sles11sp2-i386.img: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0002d3be
Device Boot Start End Blocks Id System
sles11sp2-i386.img1 2048 4208639 2103296 82 Linux swap / Solaris
Partition 1 does not end on cylinder boundary.
sles11sp2-i386.img2 * 4208640 41943039 18867200 83 Linux
Partition 2 has different physical/logical endings:
phys=(1023, 254, 63) logical=(2610, 212, 34)
[iyunv@jay-linux image]# echo $((4208640*512))
2154823680
[iyunv@jay-linux image]# mount -o loop,offset=2154823680 sles11sp2-i386.img /media
[iyunv@jay-linux image]# cd /media/
[iyunv@jay-linux media]# ls
bin dev home lost+found mnt proc sbin srv sys usr
boot etc lib media opt root selinux success tmp var
[iyunv@jay-linux image]# umount /media/ | 方法二:用kpartx建立分区映射后,再mount映射后的设备即可,操作实例如下:
[iyunv@jay-linux image]# kpartx -av sles11sp2-i386.imgadd map loop3p1 (253:2): 0 4206592 linear /dev/loop3 2048add map loop3p2 (253:3): 0 37734400 linear /dev/loop3 4208640[iyunv@jay-linux image]# mount /dev/mapper/loop3p2 /media/[iyunv@jay-linux image]# ls /media/bin dev home lost+found mnt proc sbin srv sys usrboot etc lib media opt root selinux success tmp var[iyunv@jay-linux image]# umount /media/[iyunv@jay-linux image]# mount /dev/mapper/loop3p1 /media//dev/mapper/loop3p1 looks like swapspace - not mountedmount: you must specify the filesystem type(其中的交换分区,我也还不知道是否可以mount;其实mount交换分区也没意义)(使用完成后,卸载挂载点、删除映射关系即可)[iyunv@jay-linux image]# umount /media/[iyunv@jay-linux image]# kpartx -d sles11sp2-i386.imgloop deleted : /dev/loop3
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[iyunv@jay-linux image]# kpartx -av sles11sp2-i386.img
add map loop3p1 (253:2): 0 4206592 linear /dev/loop3 2048
add map loop3p2 (253:3): 0 37734400 linear /dev/loop3 4208640
[iyunv@jay-linux image]# mount /dev/mapper/loop3p2 /media/
[iyunv@jay-linux image]# ls /media/
bin dev home lost+found mnt proc sbin srv sys usr
boot etc lib media opt root selinux success tmp var
[iyunv@jay-linux image]# umount /media/
[iyunv@jay-linux image]# mount /dev/mapper/loop3p1 /media/
/dev/mapper/loop3p1 looks like swapspace - not mounted
mount: you must specify the filesystem type
(其中的交换分区,我也还不知道是否可以mount;其实mount交换分区也没意义)
(使用完成后,卸载挂载点、删除映射关系即可)
[iyunv@jay-linux image]# umount /media/
[iyunv@jay-linux image]# kpartx -d sles11sp2-i386.img
loop deleted : /dev/loop3 | 关于LVM的mount,可以参考文末参考资料中的vpsee的文章(我也是试多次没做成功,才偶然看到这篇文章的),我对镜像文件中LVM分区的mount操作如下供参考。
[iyunv@jay-linux image]# fdisk -lu rhel6u2.imgYou must set cylinders.You can do this from the extra functions menu.Disk rhel6u2.img: 0 MB, 0 bytes255 heads, 63 sectors/track, 0 cylinders, total 0 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x00048b34Device Boot Start End Blocks Id Systemrhel6u2.img1 * 2048 1026047 512000 83 LinuxPartition 1 does not end on cylinder boundary.rhel6u2.img2 1026048 104857599 51915776 8e Linux LVMPartition 2 has different physical/logical endings:phys=(1023, 254, 63) logical=(6527, 21, 22)[iyunv@jay-linux image]# echo $((1026048*512))525336576[iyunv@jay-linux image]# losetup /dev/loop0 rhel6u2.img -o 525336576[iyunv@jay-linux image]# pvscanPV /dev/loop0 VG VolGroup lvm2 [49.51 GiB / 0 free]Total: 1 [49.51 GiB] / in use: 1 [49.51 GiB] / in no VG: 0 [0 ][iyunv@jay-linux image]# vgchange -ay VolGroup2 logical volume(s) in volume group "VolGroup" now active[iyunv@jay-linux image]# lvsLV VG Attr LSize Pool Origin Data% Move Log Copy% Convertlv_root VolGroup -wi-a--- 45.57glv_swap VolGroup -wi-a--- 3.94g[iyunv@jay-linux image]# mount /dev/VolGroup/lv_root /media/[iyunv@jay-linux image]# ls /media/bin cgroup etc lib lost+found misc net proc sbin srv tmp varboot dev home lib64 media mnt opt root selinux sys usr(使用完后的卸载操作,如下)[iyunv@jay-linux image]# umount /media/[iyunv@jay-linux image]# vgchange -an VolGroup0 logical volume(s) in volume group "VolGroup" now active[iyunv@jay-linux image]# losetup -d /dev/loop0
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[iyunv@jay-linux image]# fdisk -lu rhel6u2.img
You must set cylinders.
You can do this from the extra functions menu.
Disk rhel6u2.img: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00048b34
Device Boot Start End Blocks Id System
rhel6u2.img1 * 2048 1026047 512000 83 Linux
Partition 1 does not end on cylinder boundary.
rhel6u2.img2 1026048 104857599 51915776 8e Linux LVM
Partition 2 has different physical/logical endings:
phys=(1023, 254, 63) logical=(6527, 21, 22)
[iyunv@jay-linux image]# echo $((1026048*512))
525336576
[iyunv@jay-linux image]# losetup /dev/loop0 rhel6u2.img -o 525336576
[iyunv@jay-linux image]# pvscan
PV /dev/loop0 VG VolGroup lvm2 [49.51 GiB / 0 free]
Total: 1 [49.51 GiB] / in use: 1 [49.51 GiB] / in no VG: 0 [0 ]
[iyunv@jay-linux image]# vgchange -ay VolGroup
2 logical volume(s) in volume group "VolGroup" now active
[iyunv@jay-linux image]# lvs
LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert
lv_root VolGroup -wi-a--- 45.57g
lv_swap VolGroup -wi-a--- 3.94g
[iyunv@jay-linux image]# mount /dev/VolGroup/lv_root /media/
[iyunv@jay-linux image]# ls /media/
bin cgroup etc lib lost+found misc net proc sbin srv tmp var
boot dev home lib64 media mnt opt root selinux sys usr
(使用完后的卸载操作,如下)
[iyunv@jay-linux image]# umount /media/
[iyunv@jay-linux image]# vgchange -an VolGroup
0 logical volume(s) in volume group "VolGroup" now active
[iyunv@jay-linux image]# losetup -d /dev/loop0 | mount LVM 分区的 参考资料:
Related posts:
- 如何挂载qcow2格式的镜像文件(how to mount a qcow2 image)
- Linux挂载NTFS分区:mount unknown filesystem type ‘ntfs’
- Ubuntu上的android sdk: ./emulator: No such file or directory
- “mount: could not find any free loop device”解决方案
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