已索引
How do I move a Volume Group from one system to another?
SOLUTION VERIFIED - Updated December 7 2014 at 7:32 AM - English
Environment
Red Hat Enterprise Linux & LVM
Issue
How do I move a Volume Group from one system to another?
Resolution
To move a whole volume group from one system to a new system, the vgexport and vgimport commands can be used.
Note: These steps are only for the local disk, not for the Directl Lun mapped to the system.
When vgexport or vgimport is used, it is not necessary to move drives from one system to another. It is an administrative policy tool to prevent access to volumes while moving them to another system.
In this example we will run through the steps to move a volume group named design from one system to another. A logical volume from this volume group is initially mounted at /mnt/design/users:
源主机上操作
Umount the file system ( If required make use of "rescue" mode ). Make sure that no users are accessing files on the active volume.
# umount /mnt/design/usersMark the volume group inactive. Marking the volume group inactive removes it from the kernel and prevents any further activity on it.
# vgchange -an design
vgchange -- volume group "design" successfully deactivatedExport the volume group. This prevents it from being accessed on the "old" host system and prepares it to be removed.
# vgexport design
vgexport -- volume group "design" successfully exportedWhen the machine is shut down, the disk can be unplugged and then connected to it's new machine.
目标主机上操作
When plugged into the new system it becomes /dev/sdb so an initial pvscan shows:
# pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- inactive PV "/dev/sdb1" is in EXPORTED VG "design" [996 MB / 996 MB free]
pvscan -- inactive PV "/dev/sdb2" is in EXPORTED VG "design" [996 MB / 244 MB free]
pvscan -- total: 2 [1.95 GB] / in use: 2 [1.95 GB] / in no VG: 0 [0]Import the volume group.
- If importing on an LVM 2 system, run:
# vgimport design
Volume group "design" successfully imported- If importing on an LVM 1 system, add the PVs that need to be imported:
# vgimport design /dev/sdb1 /dev/sdb2
vgimport -- doing automatic backup of volume group "design"
vgimport -- volume group "design" successfully imported and activatedActivate the volume group.
# vgchange -ay designMount the file system.
# mkdir -p /mnt/design/users
# mount /dev/design/users /mnt/design/usersTo make the change persistent after a system reboot put the entry in /etc/fstab file.
案例记录
一台主机因为开发人员不懂Linux系统，按照网上的文章强制安装了 gcc 相关的一堆软件包，严重破坏了系统的 GLIBC 库，ssh 服务和 yum/rpm 等命令都不可用，报错信息类似如下：
rpm: /lib64/libc.so.6: version 'GLIBC_2.14' not found (required by /usr/lib64/libz.so.1)
计划给开发人员重新部署一台测试用机，但是要保留原主机下的应用程序文件。
于是将原主机的磁盘挂载到新主机上后，lsblk可以看到新磁盘有两个分区：
[root@newhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 512M 0 part /boot
├─sda2 8:2 0 32G 0 part [SWAP]
└─sda3 8:3 0 167.5G 0 part
├─VG-LogVol_root (dm-0) 253:0 0 99G 0 lvm /
└─VG-LogVol_tmp (dm-1) 253:1 0 20G 0 lvm /tmp
sdb 8:16 0 100G 0 disk
├─sdb1 8:17 0 500M 0 part
└─sdb2 8:18 0 79.5G 0 part 尝试挂载故障主机磁盘时提示是 LVM 磁盘：
[root@newhost ~]# mkdir /mnt/tmp
[root@newhost ~]# mount /dev/sdb2 /mnt/tmp
mount: unknown filesystem type 'LVM2_member'检查当时 LVM 的状态，未发现故障主机磁盘相关的LVM信息：
[root@newhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VG 1 2 0 wz--n- 167.50g 48.50g
[root@newhost ~]#
[root@newhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 VG lvm2 a-- 167.50g 48.50g执行 pvscan 进行发现操作：
[root@newhost ~]# pvscan
PV /dev/sdb2 VG rootvg lvm2 [79.50 GiB / 0 free]
PV /dev/sda3 VG VG lvm2 [167.50 GiB / 48.50 GiB free]
Total: 2 [247.00 GiB] / in use: 2 [247.00 GiB] / in no VG: 0 [0 ]
[root@newhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 VG lvm2 a-- 167.50g 48.50g
/dev/sdb2 rootvg lvm2 a-- 79.50g 0
[root@newhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VG 1 2 0 wz--n- 167.50g 48.50g
rootvg 1 2 0 wz--n- 79.50g 0
[root@newhost ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
LogVol_root VG -wi-ao---- 99.00g
LogVol_tmp VG -wi-ao---- 20.00g
lv_root rootvg -wi------- 63.50g
lv_swap rootvg -wi------- 16.00g 现在已经发现了 LVM，但是还不能使用：
[root@newhost ~]# mount /dev/rootvg/lv_root /mnt/tmp/
mount: you must specify the filesystem type
[root@newhost ~]# ls /dev/rootvg/lv_root
ls: cannot access /dev/rootvg/lv_root: No such file or directory把 VG 激活后就可以使用了：
[root@newhost ~]# vgchange -ay rootvg
2 logical volume(s) in volume group "rootvg" now active
[root@newhost ~]# ls /dev/rootvg/lv_root
/dev/rootvg/lv_root
[root@newhost ~]# mount /dev/rootvg/lv_root /mnt/tmp/
[root@newhost ~]# df -hP
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VG-LogVol_root 98G 12G 81G 13% /
tmpfs 7.8G 0 7.8G 0% /dev/shm
/dev/sda1 488M 32M 432M 7% /boot
/dev/mapper/VG-LogVol_tmp 20G 433M 19G 3% /tmp
/dev/mapper/rootvg-lv_root 63G 26G 34G 43% /mnt/tmp总结起来就是两条命令：先 pvscan 发现，再 vgchange -ay 激活就可以使用了。
