Loading...

Backing Up LVM Data for OES File System Recovery

To recover OES file system with Logical Volume Manager (LVM), make sure to backup the required LVM data and obtain the configuration information of the original system.

About This Task

The section below illustrates the original configuration information needed for a recovery on a Red Hat 5.4 system. For simplicity, the new system hardware in this example is the same as the old system. The following steps should be performed only from the console.

Procedure

The following commands illustrate the types of data that need to be backed up to ensure a successful LVM restore.

  1. save /etc/fstab

    [root ~]# cat /etc/fstab

    /dev/VolGroup01/LogVol00 /                      ext3 defaults 1 1

    LABEL=/boot         /boot ext3 defaults 1 2

    tmpfs /dev/shm tmpfs defaults 0 0

    devpts /dev/pts devpts gid=5,mode=620 0 0

    sysfs /sys     sysfs defaults 0 0

    proc /proc proc defaults 0 0

    /dev/VolGroup01/LogVol01 swap                   swap defaults 0 0

    /dev/mapper/xyzzy-space /space ext3 acl,user_xattr,defaults 0 0

    /dev/mapper/xyzzy-extra /extra ext3 acl,user_xattr,defaults 0 0

    /dev/sdb1 /ext3 ext3 acl,user_xattr,defaults 0 0

    [root ~]#

  2. save contents of /proc/partitions

    [root ~]# cat /proc/partitions

    major minor #blocks name

    8 0 8388608 sda

    8 1 104391 sda1

    8 2 8281507 sda2

    8 16 8388608 sdb

    8 17 8385898 sdb1

    8 32 8388608 sdc

    253 0 7208960 dm-0

     253 1 1048576 dm-1

     253 2  3891200 dm-2

     253 3 4493312 dm-3

    [root ~]#

    [root ~]# fdisk -l

    Disk /dev/sda: 8589 MB, 8589934592 bytes

    255 heads, 63 sectors/track, 1044 cylinders

    Units = cylinders of 16065 * 512 = 8225280 bytes

     

    Device Boot Start End     Blocks Id System

    /dev/sda1 1 13 104391 83 Linux

    /dev/sda2 14 1044 8281507+ 8e Linux LVM

    Disk /dev/sdb: 8589 MB, 8589934592 bytes

    255 heads, 63 sectors/track, 1044 cylinders

    Units = cylinders of 16065 * 512 = 8225280 bytes

     

    Device Boot Start End Blocks Id System

    /dev/sdb1 1 1044 8385898+ 83 Linux

     

    Disk /dev/sdc: 8589 MB, 8589934592 bytes

    255 heads, 63 sectors/track, 1044 cylinders

    Units = cylinders of 16065 * 512 = 8225280 bytes

     

    Device Boot Start End Blocks Id System

    /dev/sdc1 1 1044 8385898+ 83 Linux

    [root ~]#

  3. The interactive lvm command provides information of the configuration and status of the logical volumes. Individual commands, such as pvcreate to get the UUID’s of LVM disks, vgdisplay and lvdisplay can also be used.

    [root ~]# lvm

    lvm>

    lvm> vgdisplay -v

    Finding all volume groups

    Finding volume group "VolGroup01"

    --- Volume group ---

    VG Name VolGroup01

    System ID

    Format lvm2

    Metadata Areas 1

    Metadata Sequence No 3

    VG Access read/write

    VG Status resizable

    MAX LV 0

    Cur LV 2

    Open LV 2

    Max PV 0

    Cur PV 1

    Act PV 1

    VG Size 7.88 GB

    PE Size 32.00 MB

    Total PE 252

    Alloc PE / Size 252 / 7.88 GB

    Free PE / Size 0 / 0

    VG UUID XTR8Sr-gcqw-WtKM-bi4a-fctP-0xH9-7vTsB0

     

    --- Logical volume ---

    LV Name /dev/VolGroup01/LogVol00

    VG Name VolGroup01

    LV UUID q00hUf-Xqt5-ZcL4-rErN-xEmp-EgTB-vdvdwD

    LV Write Access read/write

    LV Status available

    # open 1

    LV Size 6.88 GB

    Current LE 220

    Segments 1

    Allocation inherit

    Read ahead sectors auto

    - currently set to 256

    Block device 253:0

     

    --- Logical volume ---

    LV Name /dev/VolGroup01/LogVol01

    VG Name VolGroup01

    LV UUID 3A5SeG-PKUn-DaRm-0Bac-NPta-RdkB-N1Vx9P

    LV Write Access read/write

    LV Status available

    # open 1

    LV Size 1.00 GB

      Current LE 32

    Segments 1

    Allocation inherit

    Read ahead sectors auto

    - currently set to 256

    Block device 253:1

     

    --- Physical volumes ---

    PV Name /dev/sda2

    PV UUID W0Y0cc-g4z1-ScQd-584L-40gR-I67d-YMuQih

    PV Status allocatable

    Total PE / Free PE 252 / 0

     

     For example, to find volume group "xyzzy":

    --- Volume group ---

    VG Name xyzzy

    System ID

    Format lvm2

    Metadata Areas 1

    Metadata Sequence No 5

    VG Access read/write

    VG Status resizable

    MAX LV 0

    Cur LV 2

    Open LV 2

    Max PV 0

    Cur PV 1

    Act PV 1

    VG Size 8.00 GB

    PE Size 4.00 MB

    Total PE 2047

    Alloc PE / Size 2047 / 8.00 GB

    Free PE / Size 0 / 0

    VG UUID mRiLOx-Ehbl-upEX-bxzf-EGDS-UTiL-vIb8qt

     

    --- Logical volume ---

    LV Name /dev/xyzzy/space

    VG Name xyzzy

    LV UUID R2DKYD-ljJP-nVfI-s1Gj-NgZi-glVb-XURMyS

    LV Write Access read/write

    LV Status available

    # open   1

    LV Size 3.71 GB

    Current LE 950

    Segments 1

    Allocation inherit

    Read ahead sectors auto

    - currently set to 256

    Block device 253:2

     

    --- Logical volume ---

    LV Name            /dev/xyzzy/extra

    VG Name xyzzy

    LV UUID RtkNPS-FCcy-WOko-gSlc-J48d-Dq0J-YCnM5x

    LV Write Access read/write

    LV Status available

    # open 1

    LV Size 4.29 GB

    Current LE 1097

    Segments 1

    Allocation inherit

    Read ahead sectors auto

    - currently set to 256

    Block device 253:3

     

    --- Physical volumes ---

    PV Name /dev/sdc

    PV UUID BftPia-mJZY-8eHA-BMNf-Jv38-Mbnl-bN5ej6

    PV Status allocatable

    Total PE / Free PE 2047 / 0

  4. Exit from lvm

    vm> quit

        Exiting....

        [root ~]#

  5. The original system has three disks partitioned as follows:

        /dev/sda2 – Volume Group “VolGroup01-LogVol00”  (root)

        /dev/sda2 – Volume Group “VolGroup01-LogVol01”  (swap)

        /dev/sda1 - /boot

        /dev/sdb1 – standard ext3 file system mounted on /ext3

        /dev/sdc1 – Volume group “xyzzy”. Just a standard volume group with two logical volumes mounted to /extra and /space

  6. Perform a full system (Default) backup

        vgcfgbackup –f <%s.VG_backup>

  7. Save the current Volume Group information. Copy the output files on another box. The e %s will be replaced with the VG name being backed up. One VG will be saved per file. The parameters of the command may vary depending upon the distribution you are using.

Result

In our example two files are created: VolGroup00.VG_backupxyzzy.VG_backup

 

Last modified: 3/1/2018 8:04:43 PM