May 2, 2014 - rob

How to resize an LVM volume in Linux

If you  add more disk space to linux, we need to make the new space available to the LVM Partition. We will use “parted”. It has an interactive shell, so just enter “parted” in a shell:

parted
(parted) unit MB
(parted) print
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 10.7GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
;
Number Start End Size Type File system Flags
1 32.3kB 206MB 206MB primary ext3 boot
2 206MB 8587MB 8382MB primary lvm

So now let’s make a partition from the new space:

(parted) mkpart primary 8588 9588
;
(parted) print
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 10.7GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
;
Number Start End Size Type File system Flags
1 32.3kB 206MB 206MB primary ext3 boot
2 206MB 8587MB 8382MB primary lvm
3 8587MB 9588MB 1001MB primary

You can now see that we have allocated a total of 1001MB of space to partition 3 or /dev/sda3.

Next we need to create a Physical Volume (PV) with “pvcreate”. LVM also has an interactive shell, so type “lvm” in a shell prompt:

lvm
lvm> pvcreate /dev/sda3
Physical volume "/dev/sda3" successfully created
;
lvm> pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 7.78G 32.00M
/dev/sda3 lvm2 -- 954.44M 954.44M

Now there is a partition that is about 1GB of space available on PV /dev/sda3.

Now we need to extend the Volume Group (VG) to include the new PV with the “vgextend” command:

lvm> vgextend VolGroup00 /dev/sda3
Volume group "VolGroup00" successfully extended
lvm> pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 7.78G 32.00M
/dev/sda3 VolGroup00 lvm2 a- 928.00M 928.00M

By virtue of the fact that we used the same name as the existing VG, we have now included this PV in the VG.

Extend the Logical Volume (LV) to include the new space with “lvextend”. To determine that size of the extents we want to add, we first need to view the VG:

lvm> vgdisplay VolGroup00
--- Volume group ---
VG Name VolGroup00
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size 8.69 GB
PE Size 32.00 MB
Total PE 278
Alloc PE / Size 248 / 7.75 GB
Free PE / Size 30 / 960.00 MB
VG UUID Ll4Bg4-jIFV-lfut-z4Ae-JTfH-0Hzp-Zf9RjM

Looking at this we can see that the total “Free PE” is 30. (PE stand for Physical Extent and in this example there are 30 Physical Extents available to grow the partition) We will use this in the following command:

lvm> lvextend -l+30 /dev/VolGroup00/LogVol00
Extending logical volume LogVol00 to 8.19 GB
Logical volume LogVol00 successfully resized
;
lvm> lvs
LV VG Attr LSize Origin Snap% Move Log Copy%
LogVol00 VolGroup00 -wi-ao 8.19G
LogVol01 VolGroup00 -wi-ao 512.00M

So there you are, you have now extended your LV. Now we have to clue the OS in what is happening.We need to expand the file system to make the new space visible to the OS with resize2fs

[root@JPOSWORK]# df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
7.1G 1.3G 5.4G 20% /
;
[root@JPOSWORK]# resize2fs
resize2fs 1.40.2 (12-Jul-2007)
Usage: resize2fs [-d debug_flags] [-f] [-F] [-p] device [new_size]
;
[root@JPOSWORK]# resize2fs /dev/VolGroup00/LogVol00
resize2fs 1.40.2 (12-Jul-2007)
Filesystem at /dev/VolGroup00/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/LogVol00 to 2146304 (4k)blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 2146304 blocks long.
;
[root@JPOSWORK]# df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
8.0G 1.3G 6.3G 17% /

Linux

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