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
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