1. Overview
After having your Linux Operating Systems running on LVM partitions, it is now to gain the advantages of this. Let say one of the partition is running out of space and need to increase its disk space capacity. For this tutorial will show you how to increase the disk space capacity in /var partition.
2. Prerequisites
In this article, it is presumed that:
a. You have already install RHEL/CentOS 7 Linux server up and running on VLM partitions. In case that you don’t, you would probably like to read this link. Minimal RHEL/CentOS 7 Installation With Logical Volume Manager (LVM).
b. You have the root privilege to perform the LVM operation.
3. Create LVM Partition
Before we start to create the LVM partition, we should check available space capacity on the physical disk first. In the following output, we can see that the physical disk space capacity for /dev/sda is 32GB.
# fdisk -l | grep /dev
Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
/dev/sda1 * 2048 1050623 524288 83 Linux
/dev/sda2 1050624 40904703 19927040 8e Linux LVM
Disk /dev/mapper/vg–systems-lv–root: 4294 MB, 4294967296 bytes, 8388608 sectors
Disk /dev/mapper/vg–systems-lv–swap: 2147 MB, 2147483648 bytes, 4194304 sectors
Disk /dev/mapper/vg–systems-lv–usr: 4294 MB, 4294967296 bytes, 8388608 sectors
Disk /dev/mapper/vg–systems-lv–home: 3221 MB, 3221225472 bytes, 6291456 sectors
Disk /dev/mapper/vg–systems-lv–var: 4294 MB, 4294967296 bytes, 8388608 sectors
Disk /dev/mapper/vg–systems-lv–tmp: 2147 MB, 2147483648 bytes, 4194304 sectors
Then, we need to check how many GB of disk space that have already occupied by the Physical Volume (PV) of the LVM. As we can see in the following output, the Physical Volume /dev/sda2 have already occupied 19GB of 32GB total physical disk space. So in this case, we still have some available disk space to create more Physical Volume (PV).
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg-systems lvm2 a– 19.00g 0
In case that it is already occupied all of the available space capacity of physical disk, we need to shutdown the VM and increase the size if its virtual disk or we can add more virtual disk to this VM. Either ways are absolutely possible.
To create the LVM partition on the physical disk /dev/sda, we use fdisk command as the following. Press “p” to list the current partition on the physical disk /dev/sda.
# fdisk /dev/sda
Welcome to fdisk (util-linux 2.23.2).Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.Command (m for help): p
Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000ae829Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1050623 524288 83 Linux
/dev/sda2 1050624 40904703 19927040 8e Linux LVM
Next, we can start to create the LVM partition by press “n” as shown below. Then press “p” again and we can see that there is one new partition, /dev/sda3, now created.
Command (m for help): n
Partition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p):
Using default response p
Partition number (3,4, default 3):
First sector (40904704-62914559, default 40904704):
Using default value 40904704
Last sector, +sectors or +size{K,M,G} (40904704-62914559, default 62914559):
Using default value 62914559
Partition 3 of type Linux and of size 10.5 GiB is setCommand (m for help): p
Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000ae829Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1050623 524288 83 Linux
/dev/sda2 1050624 40904703 19927040 8e Linux LVM
/dev/sda3 40904704 62914559 11004928 83 Linux
The new created partition,/dev/sda3, is a normal Linux partition, it is not the LVM partition. Press “t” to change the partition type of /dev/sda3. To list the available partition type press “L“. Now let input “8e” to change the partition type of /dev/sda3 to be a LVM partition.
Press “p” to verify that the change and we should see now that /dev/sda3 is an LVM partition now.
Command (m for help): t
Partition number (1-3, default 3):
Hex code (type L to list all codes): L0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx
5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data
6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility
8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt
9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access
a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD ee GPT
f W95 Ext’d (LBA) 54 OnTrackDM6 a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 55 EZ-Drive a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 5c Priam Edisk a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f2 DOS secondary
16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 75 PC/IX be Solaris boot ff BBT
1e Hidden W95 FAT1 80 Old Minix
Hex code (type L to list all codes):8e
Changed type of partition ‘Linux’ to ‘Linux LVM’Command (m for help): p
Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000ae829Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1050623 524288 83 Linux
/dev/sda2 1050624 40904703 19927040 8e Linux LVM
/dev/sda3 40904704 62914559 11004928 8e Linux LVM
Press “w” to save and finish creating the VLM partition. You will see an warning message as the following that the new partition will be usable only after reboot the systems.
Command (m for help): w
The partition table has been altered!Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
So, let reboot the server with the following command.
# reboot
After reboot, verify the new created LVM partition again and we should see something as the following.
# fdisk -l | grep /dev
Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
/dev/sda1 * 2048 1050623 524288 83 Linux
/dev/sda2 1050624 40904703 19927040 8e Linux LVM
/dev/sda3 40904704 62914559 11004928 8e Linux LVM
Disk /dev/mapper/vg–systems-lv–root: 4294 MB, 4294967296 bytes, 8388608 sectors
Disk /dev/mapper/vg–systems-lv–swap: 2147 MB, 2147483648 bytes, 4194304 sectors
Disk /dev/mapper/vg–systems-lv–usr: 4294 MB, 4294967296 bytes, 8388608 sectors
Disk /dev/mapper/vg–systems-lv–home: 3221 MB, 3221225472 bytes, 6291456 sectors
Disk /dev/mapper/vg–systems-lv–var: 4294 MB, 4294967296 bytes, 8388608 sectors
Disk /dev/mapper/vg–systems-lv–tmp: 2147 MB, 2147483648 bytes, 4194304 sectors
4. Create Physical Volume
Before creating a new Physical Volume (PV), we should check the existing Physical Volume first by using the following command. We can see that there is only one partition which is /dev/sda2 in the current Physical Volume (PV).
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg-systems lvm2 a– 19.00g 0
Now let create a new Physical Volume from the LVM partition, /dev/sda3, that we have just created in the above step by executing the following command.
# pvcreate /dev/sda3
Physical volume “/dev/sda3” successfully created.
We can see that there is one more partition now in the Physical Volume (PV) which is /dev/sda3.
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg-systems lvm2 a– 19.00g 0
/dev/sda3 lvm2 — 10.50g 10.50g
5. Extend Volume Group Space
Let check the existing Volume Group (VG) that it was created during the Linux CentOS 7 Operating Systems installation process. From the following output, we can see that there is no free space on the Volume Goup (VG) name “vg-systems”.
# vgs
VG #PV #LV #SN Attr VSize VFree
vg-systems 1 6 0 wz–n- 19.00g 0
So now, let extend the Volume Group (VG) name “vg-systems” from Physical Volume (PV) /dev/sda3 as the following.
# vgextend vg-systems /dev/sda3
Volume group “vg-systems” successfully extended
If we check the Volume Group (VG) again, we will see that there is some available free space now on the Volume Group (VG) name “vg-systems”.
# vgs
VG #PV #LV #SN Attr VSize VFree
vg-systems 2 6 0 wz–n- 29.49g 10.49g
Also, if we check the Physical Volume (PV) again, we can see that there are two partitions in the existing Physical Volume (PV).
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg-systems lvm2 a– 19.00g 0
/dev/sda3 vg-systems lvm2 a– 10.49g 10.49g
6. Extend Logical Volume Space
To extend the Logical Volume (LV) disk space, we need to know the path of that particular Logical Volume (LV) by using command lvscan as the following.
# lvscan
ACTIVE ‘/dev/vg-systems/lv-root’ [4.00 GiB] inherit
ACTIVE ‘/dev/vg-systems/lv-home’ [3.00 GiB] inherit
ACTIVE ‘/dev/vg-systems/lv-var’ [4.00 GiB] inherit
ACTIVE ‘/dev/vg-systems/lv-swap’ [2.00 GiB] inherit
ACTIVE ‘/dev/vg-systems/lv-usr’ [4.00 GiB] inherit
ACTIVE ‘/dev/vg-systems/lv-tmp’ [2.00 GiB] inherit
Since we want to extend the disk space capacity of the /var partition, so let execute the following command.
# lvextend -L 8G /dev/vg-systems/lv-var
Size of logical volume vg-systems/lv-var changed from 4.00 GiB (1024 extents) to 8.00 GiB (2048 extents).
Logical volume vg-systems/lv-var successfully resized.
Verity the disk pace of the Logical Volume (LV) “lv-var” again. We should see that the space capacity of the Logical Volume (LV) “lv-var” has increased to 8GB.
# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv-home vg-systems -wi-ao—- 3.00g
lv-root vg-systems -wi-ao—- 4.00g
lv-swap vg-systems -wi-ao—- 2.00g
lv-tmp vg-systems -wi-ao—- 2.00g
lv-usr vg-systems -wi-ao—- 4.00g
lv-var vg-systems -wi-ao—- 8.00g
However, we still see the disk space of /var partition is 4GB.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg–systems-lv–root 4.0G 65M 4.0G 2% /
devtmpfs 478M 0 478M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 6.6M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/mapper/vg–systems-lv–usr 4.0G 1.6G 2.5G 39% /usr
/dev/sda1 509M 172M 338M 34% /boot
/dev/mapper/vg–systems-lv–tmp 2.0G 33M 2.0G 2% /tmp
/dev/mapper/vg–systems-lv–var 4.0G 280M 3.8G 7% /var
/dev/mapper/vg–systems-lv–home 3.0G 33M 3.0G 2% /home
tmpfs 98M 0 98M 0% /run/user/1000
To resize the /var partition, which was formatted as XFS file system, execute the following command.
# xfs_growfs /var/
meta-data=/dev/mapper/vg–systems-lv–var isize=256 agcount=4, agsize=262144 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0 finobt=0 spinodes=0
data = bsize=4096 blocks=1048576, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal 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 1048576 to 2097152
Let check the disk space of /var partition again. We see it is updated to 8GB now.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg–systems-lv–root 4.0G 65M 4.0G 2% /
devtmpfs 478M 0 478M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 6.6M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/mapper/vg–systems-lv–usr 4.0G 1.6G 2.5G 39% /usr
/dev/sda1 509M 172M 338M 34% /boot
/dev/mapper/vg–systems-lv–tmp 2.0G 33M 2.0G 2% /tmp
/dev/mapper/vg–systems-lv–var 8.0G 280M 7.8G 4% /var
/dev/mapper/vg–systems-lv–home 3.0G 33M 3.0G 2% /home
tmpfs 98M 0 98M 0% /run/user/1000
If we check the Volume Group (VG) again we can see that the free space is decreased now.
# vgs
VG #PV #LV #SN Attr VSize VFree
vg-systems 2 6 0 wz–n- 29.49g 6.49g
Let reboot the system to make sure that your server is still bootable after extending the disk space of Logical Volume “lv-var”.
# reboot
6. Conclusion
Now you should know about how to increase the disk space on your LVM partition. It is recommended that you practice it on VMware workstation to improve your confidence before apply it on production environment. If you have any questions or suggestions you can always leave your comments below. I will try all of my best to review and reply them.
