Chapter 5. Modifying the size of a logical volume

Prerequisites

1. You have an existing logical volume (LV) with a file system on it. Determine the file system type by using the df -Th command.

   For more information on creating LV and a file system, see Creating LVM logical volume.

2. You have sufficient space in the volume group to grow your LV and file system. Use the vgs -o name,vgfree command to determine the available space.

Procedure

1. Optional: If the volume group has insufficient space to grow your LV, then add a new physical volume to the volume group by using the following command:

   # vgextend myvg /dev/vdb3
   Physical volume "/dev/vdb3" successfully created.
   Volume group "myvg" successfully extended

   For more information, see Creating LVM volume group.

2. Now that the volume group is large enough, execute any one of the following steps as per your requirement:

   1. To extend the LV with the provided size, use the following command:

      # lvextend -L 3G /dev/myvg/mylv
      Size of logical volume myvg/mylv changed from 2.00 GiB (512 extents) to 3.00 GiB (768 extents).
      Logical volume myvg/mylv successfully resized.

      Note

      You can use the -r option of the lvextend command to extend the logical volume and resize the underlying file system with a single command:

      # lvextend -r -L 3G /dev/myvg/mylv

      Warning

      You can also extend the logical volume using the lvresize command with the same arguments, but this command does not guarantee against accidental shrinkage.

   2. To extend the mylv logical volume to fill all of the unallocated space in the myvg volume group, use the following command:

      # lvextend -l +100%FREE /dev/myvg/mylv
       Size of logical volume myvg/mylv changed from 10.00 GiB (2560 extents) to 6.35 TiB (1665465 extents).
       Logical volume myvg/mylv successfully resized.

      As with the lvcreate command, you can use the -l argument of the lvextend command to specify the number of extents by which to increase the size of the logical volume. You can also use this argument to specify a percentage of the volume group, or a percentage of the remaining free space in the volume group.

3. If you are not using the r option with the lvextend command to extend the LV and resize the file system with a single command, then resize the file system on the logical volume by using the following command:

   xfs_growfs /mnt/mnt1/
   meta-data=/dev/mapper/myvg-mylv  isize=512    agcount=4, agsize=65536 blks
            =                       sectsz=512   attr=2, projid32bit=1
            =                       crc=1        finobt=1, sparse=1, rmapbt=0
            =                       reflink=1
   data     =                       bsize=4096   blocks=262144, imaxpct=25
            =                       sunit=0      swidth=0 blks
   naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
   log      =internal log           bsize=4096   blocks=2560, version=2
            =                       sectsz=512   sunit=0 blks, lazy-count=1
   realtime =none                   extsz=4096   blocks=0, rtextents=0
   data blocks changed from 262144 to 524288

   Note

   Without the -D option, xfs_growfs grows the file system to the maximum size supported by the underlying device. For more information, see Increasing the size of an XFS file system.

   For resizing an ext4 file system, see Resizing an ext4 file system.