HowTo Change The LVM Volume Group Name That Includes The Root Partition

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Revision as of 15:20, 1 January 2014 by Rwh (talk | contribs) (Steps To Change The LVM Volume Group Name)
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Overview

This page describes the steps needed to change an LVM (Logical Volume Manager) Volume Group name which includes the the Root partition ("/"). The problem is that the Root partition LVM Device Mapper is referenced in different configuration files and embedded in the Kernel initramfs.

We will demonstrate the LVM Volume Group name change from "nst_localhost" to "nst20".

State Before The LVM Volume Group Name Change

The Fedora System Storage Manager utility: ssm is used to display the current storage layout on the example system.

[root@localhost ~]# ssm list
-------------------------------------------------------------------
Device        Free      Used      Total  Pool           Mount point  
-------------------------------------------------------------------
/dev/sda                       30.00 GB                 PARTITIONED  
/dev/sda1                     500.00 MB                 /boot        
/dev/sda2  0.00 KB  29.51 GB   29.51 GB  nst_localhost               
-------------------------------------------------------------------
---------------------------------------------------------
Pool           Type  Devices     Free      Used     Total  
---------------------------------------------------------
nst_localhost  lvm   1        0.00 KB  29.51 GB  29.51 GB  
---------------------------------------------------------
----------------------------------------------------------------------------------------------------
Volume                   Pool           Volume size  FS      FS size       Free  Type    Mount point  
----------------------------------------------------------------------------------------------------
/dev/nst_localhost/root  nst_localhost     27.48 GB  ext4   27.48 GB   19.18 GB  linear  /            
/dev/nst_localhost/swap  nst_localhost      2.03 GB                              linear               
/dev/sda1                                 500.00 MB  ext4  500.00 MB  364.40 MB  part    /boot        
----------------------------------------------------------------------------------------------------

Steps To Change The LVM Volume Group Name

Step 1: Change Volume Group Name

The vgrename utility will be used to change LVM Volume Name from "nst_localhost" to "nst20":

[root@localhost ~]# vgrename -v nst_localhost nst20
    Checking for existing volume group "nst_localhost"
    Checking for new volume group "nst20"
    Archiving volume group "nst_localhost" metadata (seqno 5).
    Writing out updated volume group
    Renaming "/dev/nst_localhost" to "/dev/nst20"
    Loading nst_localhost-root table (253:0)
    Suppressed nst_localhost-root (253:0) identical table reload.
    Suspending nst_localhost-root (253:0) with device flush
    Loading nst_localhost-root table (253:0)
    Suppressed nst_localhost-root (253:0) identical table reload.
    Renaming nst_localhost-root (253:0) to nst20-root
    Resuming nst20-root (253:0)
    Loading nst_localhost-swap table (253:1)
    Suppressed nst_localhost-swap (253:1) identical table reload.
    Suspending nst_localhost-swap (253:1) with device flush
    Loading nst_localhost-swap table (253:1)
    Suppressed nst_localhost-swap (253:1) identical table reload.
    Renaming nst_localhost-swap (253:1) to nst20-swap
    Resuming nst20-swap (253:1)
    Creating volume group backup "/etc/lvm/backup/nst20" (seqno 6).
  Volume group "nst_localhost" successfully renamed to "nst20"
    Wiping cache of LVM-capable devices
    Wiping internal VG cache

Step 2: Update The File System Configuration File: "/etc/fstab"

Use an editor (e.g., vi) to change the LVM Volume Group Device Mapper name in the file system configuration file: "/etc/fstab" to the new "nst20" name for the "root" and "swap" Logical Volumes.

Before:

[root@localhost ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Mon Dec 30 05:16:54 2013
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/nst_localhost-root /                       ext4    defaults        1 1
UUID=8c72887d-d7db-4a3d-9b09-0d619fc11d9c /boot                   ext4    defaults        1 2
/dev/mapper/nst_localhost-swap swap                    swap    defaults        0 0

After:

[root@localhost ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Mon Dec 30 05:16:54 2013
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/nst20-root /                       ext4    defaults        1 1
UUID=8c72887d-d7db-4a3d-9b09-0d619fc11d9c /boot                   ext4    defaults        1 2
/dev/mapper/nst20-swap swap                    swap    defaults        0 0