Moving Volume Groups between hosts in RHEL

This is a fairly straight-forward process.

1. Exporting the volume group from its current host
   • Unmount any LV residing on that particular VG. In my case, there’s only one LV on VG vg0
     • list all lv in the vg

       [root@hqhcmdev1 ~]# lvdisplay 
       --- Logical volume --- 
       LV Name                /dev/vg0/lvol0 
       VG Name                vg0 
       LV UUID                7HltCU-Elaq-x1pr-S7Wm-xvOt-NGk6-Fwufyd 
       LV Write Access        read/write 
       LV Status              NOT available 
       LV Size                97.47 GB 
       Current LE             6238 
       Segments               1 
       Allocation             inherit 
       Read ahead sectors     0

     • unmount the lv

       [root@hqhcmdev1 ~]# umount /u01

     • if there’s any, remove the fstab entry for that particular partition, so that the booting process will not try to mount the partition

       [root@hqhcmdev1 ~]# vi /etc/fstab

       The /etc/fstab should look like this:

       # This file is edited by fstab-sync - see 'man fstab-sync' for details 
       /dev/VolGroup00/LogVol00 /     ext3     defaults 1 1 
       LABEL=/boot         /boot     ext3     defaults 1 2 none 
       /dev/pts         devpts         gid=5,mode=620 0 0 none 
       /dev/shm             tmpfs     defaults 0 0 none 
       /proc                 proc     defaults 0 0 none 
       /sys                 sysfs     defaults 0 0 
       /dev/VolGroup00/LogVol01 swap     swap     defaults 0 0 
       #LABEL=/u01         /u01     ext3     defaults 1 1
       

   • Deactivate, and export the volume group
     • Deactivating vg0

       [root@hqhcmdev1 ~]# vgchange -an vg0 
       0 logical volume(s) in volume group "vg0" now active

     • exporting vg0

       [root@hqhcmdev1 ~]# vgexport vg0 
       file system Volume group "vg0" successfully exported

2. Import the volume group to the new server
   • Present the exported partition to the new server
     • Search for the new partition This step depends on what hardware are you using for the storage. Some SANs provide it’s own tool, and others use linux generic command such as:

        [root@hqhcmdev2 ~]# echo "- - -" > /sys/class/scsi_host/host0/scan

     • Check whether the partition has been detected by the target server using pvscan

       [root@hqhcmdev2 ~]# pvscan 
       PV /dev/sda2     VG VolGroup00 lvm2     [19.88 GB / 0 free]  
       PV /dev/sdb1 is in exported VG vg0     [99.98 GB / 2.52 GB free] 
       PV /dev/sdd1     VG VolGroup00 lvm2     [3.97 GB / 128.00 MB free] 
       Total: 3 [123.83 GB] / in use: 3 [123.83 GB] / in no VG: 0 [0    ]
       

   • Activate and import the volumegroup
     • Import the VG

       [root@hqhcmdev2 ~]# vgimport vg0 
       Volume group "vg0" successfully imported

     • Activate the VG

        [root@hqhcmdev2 ~]# vgchange -ay vg0

   • Mount the imported partition
     • Create a mountpoint for the imported partition

        [root@hqhcmdev2 ~]# mkdir /t01

     • label the partition First, look for the logical volume residing on the newly imported partition

       [root@hqhcmdev2 ~]# lvdisplay vg0 
       --- Logical volume --- 
       LV Name     /dev/vg0/lvol0 VG Name vg0 
       LV UUID     7HltCU-Elaq-x1pr-S7Wm-xvOt-NGk6-Fwufyd 
       LV Write Access read/write 
       LV Status     available 
       # open         1 
       LV Size     97.47 GB 
       Current LE     6238 
       Segments     1 
       Allocation     inherit 
       Read ahead     sectors 0 
       Block device     253:2

       Next, create a label for that LV

       [root@hqhcmdev2 ~]# e2label /dev/vg0/lvol0 /t01

     • optionally, create a fstab entry for the partition, if you want it to be automatically mounted on reboot

       [root@hqhcmdev2 ~]# vi /etc/fstab

       The /etc/fstab should look like this:

        This file is edited by fstab-sync - see 'man fstab-sync' for details 
       /dev/VolGroup00/LogVol00 /     ext3     defaults 1 1 
       LABEL=/boot         /boot     ext3     defaults 1 2 none 
       /dev/pts             devpts     gid=5,mode=620 0 0 none 
       /dev/shm             tmpfs     defaults 0 0 none 
       /proc                 proc     defaults 0 0 none 
       /sys                 sysfs     defaults 0 0 
       /dev/VolGroup00/LogVol01 swap     swap     defaults 0 0 
       LABEL=/t01         /t01     ext3     defaults 1 1

     • Mount the partition

       [root@hqhcmdev1 ~]# mount /t01