Increase an existing LVM

October 15, 2011

Increase an existing LV

Taken from my LVM management notes. I had first used this when I imaged an 80GB drive to a 120GB drive and wanted to make use of the 40GB of free space.

1. fdisk /dev/sda then press p

Code:

Disk /dev/sda: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 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        1188     9438187+  8e  Linux LVM

2. Press d then 2 to remove the partition
3. Press n then primary p start cylinder 14 last cylinder 4865 to add the newly re-sized partition. WARNING: Make sure the old and new partition start at the same cylinder position, not doing so will destroy your data.
4. Press t partition 2 Hex code 8e
5. Press p

Code:

Disk /dev/sda: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 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        4865    38973690   8e  Linux LVM

6. Finally press w write table to disk and exit and reboot
7. Use vgdisplay, pvdisplay, or lvdisplay to show the current and later ending size of your LV
8. Run pvresize /dev/sda2 to expand the PV on /dev/sda2 after enlarging the partition with fdisk
9. You could also extend the volume group across disks and partitions: pvcreate /dev/hdb1; vgextend videovg /dev/hdb1; vgdisplay videovg. With this method use fdisk to create a new partition instead of recreating the original one. This is certainly safer since there is less risk to your existing data and it makes it easier to break up volume groups in the future.
10. Use vgdisplay to find the Free PE / Size

Code:

  --- Volume group ---
  VG Name               SystemVG
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  7
  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               37.17 GB
  PE Size               4.00 MB
  Total PE              9515
  Alloc PE / Size       2176 / 8.50 GB
  Free  PE / Size       7339 / 28.67 GB
  VG UUID               Bl4LEQ-R70i-3Qse-9z1p-BRcK-ibd7-2aelYx

11. Use lvdisplay to display current logical volumes

Code:

  --- Logical volume ---
  LV Name                /dev/SystemVG/RootLV
  VG Name                SystemVG
  LV UUID                dxB6Fs-6sQr-AaLg-1zQ6-Q1f9-AN6V-cbSovF
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                8.00 GB
  Current LE             2048
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0

  --- Logical volume ---
  LV Name                /dev/SystemVG/SwapLV
  VG Name                SystemVG
  LV UUID                vSRWGx-zy8N-FrXK-3HP5-7pwW-F6SQ-IRJNeA
  LV Write Access        read/write
  LV Status              available
  # open                 2
  LV Size                512.00 MB
  Current LE             128
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:1

12. lvextend -l +7339 /dev/SystemVG/RootLV (you can use the following to reduce again lvreduce -l –7339 /dev/SystemVG/RootLV)
13. lvdisplay /dev/SystemVG/RootLV to see the result

Code:

  --- Logical volume ---
  LV Name                /dev/SystemVG/RootLV
  VG Name                SystemVG
  LV UUID                dxB6Fs-6sQr-AaLg-1zQ6-Q1f9-AN6V-cbSovF
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                36.67 GB
  Current LE             9387
  Segments               2
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0

14. ext2online /dev/SystemVG/RootLV while the filesystem is mounted or to be safe use resize2fs /dev/SystemVG/RootLV while the filesystem is unmounted. Note:resize2fs may require running e2fsck -f /dev/SystemVG/RootLV first.

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Increase an existing LVM

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