By default, all ProComputers LVM-partitioned RHEL 7, CentOS 7 and Oracle Linux 7 images are configured with a default 16 GiB disk volume, that is usually split like this:
$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1 259:0 0 16G 0 disk
├─nvme0n1p1 259:1 0 1M 0 part
├─nvme0n1p2 259:2 0 512M 0 part /boot
└─nvme0n1p3 259:3 0 15.5G 0 part
├─rootvg-rootlv 253:0 0 4G 0 lvm /
├─rootvg-tmplv 253:1 0 2G 0 lvm /tmp
├─rootvg-usrlv 253:2 0 2G 0 lvm /usr
├─rootvg-optlv 253:3 0 2G 0 lvm /opt
├─rootvg-homelv 253:4 0 2G 0 lvm /home
└─rootvg-varlv 253:5 0 3.5G 0 lvm /var
The above command output tells the following:
- There is a 16 GiB disk volume
nvme0n1attached to the virtual machine (nvme0n1 259:0 0 16G 0 disk) - There are 3 partitions on this disk volume, like below:
nvme0n1p1- the first partition that is 1 MiB in size (nvme0n1p1 259:1 0 1M 0 part).nvme0n1p2- the boot partition (or the partition number 2) that is 512 MiB in size.(nvme0n1p2 259:2 0 512M 0 part /boot).nvme0n1p3- the 3rd partition that is 15.5 GiB in size (nvme0n1p3 259:3 0 15.5G 0 part).
- The partition number 3 (
nvme0n1p3) is further split in 6 filesystems, using Logical Volume Manager or LVM. - The LVM volume group is called
rootvg. - The LVM logical volume groups and corresponding filesystems are the following:
rootlvor the root (/) filesystem that is 4 GiB in size;tmplvor the tmp (/tmp) filesystem that is 2 GiB in size;usrlvor the usr (/usr) filsystem that is 2 GiB in size;optlvor the opt (/opt) filesystem that is 2 GiB in size;homelvor the home (/home) filesystem that is 2 GiB in size;varlvor the var (/var) filesystem that us 3.5 GiB in size.
The above filesystem sizes are not enough in all situations, therefore this article describes the steps required to increase their size.
To effectively use this documentation article, it’s essential to have a solid working knowledge of CentOS Linux. This includes familiarity with the command line, file system structure, basic file operations, LVM (Local Volume Manager) and system configuration.
IMPORTANT : As with any partition / filesystem / LVM change, it is very important to prepare well. Make sure you test in advance this procedure using a test virtual machine. Also, make sure you have backups and/or snapshots of your virtual machine before performing the actual change. PROCOMPUTERS SHALL NOT BE HELD LIABLE FOR ANY LOSS, DAMAGE, OR DISRUPTION RESULTING FROM THE UPGRADE PROCESS. THIS INCLUDES, BUT IS NOT LIMITED TO, DATA LOSS, SERVICE INTERRUPTIONS, OR ANY OTHER ADVERSE EFFECTS THAT MAY ARISE.
To change the size of your filesystems, please follow the steps below.
As an example, the /usr and /var filesystem sizes will be increase with 2 GiB each.
- First, we will need to increase the disk volume attached to the virtual machine with 4 GiB (2 Gib for the
/usrfilesystem and 2 GiB for the/varfilesystem).
- In case your VM is running in AWS, use this AWS document to change the root volume size from 16Gib to 20 GiB.
- After the disk volume size is changed to 20 GiB, you should be able to see this line
nvme0n1 259:0 0 20G 0 diskwithin thelsblkcommand output like below:
]$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1 259:0 0 20G 0 disk
├─nvme0n1p1 259:1 0 1M 0 part
├─nvme0n1p2 259:2 0 512M 0 part /boot
└─nvme0n1p3 259:3 0 15.5G 0 part
├─rootvg-rootlv 253:0 0 4G 0 lvm /
├─rootvg-tmplv 253:1 0 2G 0 lvm /tmp
├─rootvg-usrlv 253:2 0 2G 0 lvm /usr
├─rootvg-optlv 253:3 0 2G 0 lvm /opt
├─rootvg-homelv 253:4 0 2G 0 lvm /home
└─rootvg-varlv 253:5 0 3.5G 0 lvm /var
- Extent the 3rd partition
nvme0n1p3with 4 GiB using the maximum free available space we have just added.
- Relocate backup GPT data structures at the end of the
nvme0n1disk
$ sudo sgdisk --move-second-header /dev/nvme0n1
Warning: The kernel is still using the old partition table.
The new table will be used at the next reboot.
The operation has completed successfully.
- Extend the 3rd partition on the
nvme0n1disk to maximum available space
sudo parted --script /dev/nvme0n1 "resizepart 3 100%"
- Inform the kernel about the changes on the 3rd partiton
$ sudo partx --update --nr 3 /dev/nvme0n1
- To validate the above changes (
nvme0n1p3partition size increased with 4 GiB from 15.5 GiB to 19.5 GiB), you should be able to see this linenvme0n1p3 259:3 0 19.5G 0 partwithin thelsblkcommand output like below:
$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1 259:0 0 20G 0 disk
├─nvme0n1p1 259:1 0 1M 0 part
├─nvme0n1p2 259:2 0 512M 0 part /boot
└─nvme0n1p3 259:3 0 19.5G 0 part
├─rootvg-rootlv 253:0 0 4G 0 lvm /
├─rootvg-tmplv 253:1 0 2G 0 lvm /tmp
├─rootvg-usrlv 253:2 0 2G 0 lvm /usr
├─rootvg-optlv 253:3 0 2G 0 lvm /opt
├─rootvg-homelv 253:4 0 2G 0 lvm /home
└─rootvg-varlv 253:5 0 3.5G 0 lvm /var
- Extend the LVM physical volume size (with 4 GiB from 15.5 GiB to 19.5 GiB) to the maximum available space on the
nvme0n1p3partition:
$ sudo pvresize /dev/nvme0n1p3
Physical volume "/dev/nvme0n1p3" changed
1 physical volume(s) resized or updated / 0 physical volume(s) not resized
$ sudo pvdisplay /dev/nvme0n1p3
--- Physical volume ---
PV Name /dev/nvme0n1p3
VG Name rootvg
PV Size <19.50 GiB / not usable 16.50 KiB
Allocatable yes
PE Size 4.00 MiB
Total PE 4991
Free PE 1024
Allocated PE 3967
PV UUID MFrfyd-UoXH-a72E-aUtE-UbdH-ziRR-hvrZSS
- Extend the
usrlvLVM logical volume group and corresponding filesystem size with 2 GiB, from 2 GiB to 4 GiB:
$ sudo lvextend --resizefs --size +2G /dev/rootvg/usrlv
Size of logical volume rootvg/usrlv changed from 2.00 GiB (512 extents) to 4.00 GiB (1024 extents).
Logical volume rootvg/usrlv successfully resized.
meta-data=/dev/mapper/rootvg-usrlv isize=512 agcount=4, agsize=131072 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=524288, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
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 524288 to 1048576
- Extend the
varlvLVM logical volume group and corresponding filesystem size with maximum free available space, from 3.5 GiB to 5.5 GiB:
$ sudo lvextend --resizefs --extents +100%FREE /dev/rootvg/varlv
Size of logical volume rootvg/varlv changed from <3.50 GiB (895 extents) to <5.50 GiB (1407 extents).
Logical volume rootvg/varlv successfully resized.
meta-data=/dev/mapper/rootvg-varlv isize=512 agcount=4, agsize=229120 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=916480, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
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 916480 to 1440768
- To validate the above changes, you should be able to see this line
rootvg-usrlv 253:2 0 4G 0 lvm /usrand this linerootvg-varlv 253:5 0 5.5G 0 lvm /varwithin thelsblkcommand output like below:
$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1 259:0 0 20G 0 disk
├─nvme0n1p1 259:1 0 1M 0 part
├─nvme0n1p2 259:2 0 512M 0 part /boot
└─nvme0n1p3 259:3 0 19.5G 0 part
├─rootvg-rootlv 253:0 0 4G 0 lvm /
├─rootvg-tmplv 253:1 0 2G 0 lvm /tmp
├─rootvg-usrlv 253:2 0 4G 0 lvm /usr
├─rootvg-optlv 253:3 0 2G 0 lvm /opt
├─rootvg-homelv 253:4 0 2G 0 lvm /home
└─rootvg-varlv 253:5 0 5.5G 0 lvm /var
- You may reboot to make sure you have a clean start of your virtual machine when using the modified disk volume, however this is not required.
$ sudo reboot
References
- How to resize a logical volume with 5 simple LVM commands
- Modify a volume using Amazon EBS Elastic Volumes
For any questions related to this article, please contact ProComputers Support.
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