Resize an OS disk that has a GPT partition
Note
This article applies only to OS disks that have a GUID Partition Table (GPT) partition.
This article describes how to increase the size of an OS disk that has a GPT partition in Linux.
Identify whether the OS disk has an MBR or GPT partition
Use the parted command to identify if the disk partition has been created with either a master boot record (MBR) partition or a GPT partition.
MBR partition
In the following output, Partition Table shows a value of msdos. This value identifies an MBR partition.
[user@myvm ~]# parted -l /dev/sda
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 107GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 1049kB 525MB 524MB primary ext4 boot
2 525MB 34.4GB 33.8GB primary ext4
[user@myvm ~]#
GPT partition
In the following output, Partition Table shows a value of gpt. This value identifies a GPT partition.
[user@myvm ~]# parted -l /dev/sda
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 68.7GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 525MB 524MB fat16 EFI System Partition boot
2 525MB 1050MB 524MB xfs
3 1050MB 1052MB 2097kB bios_grub
4 1052MB 68.7GB 67.7GB lvm
If your virtual machine (VM) has a GPT partition on your OS disk, increase the size of the OS disk.
Increase the size of the OS disk
The following instructions apply to Linux-endorsed distributions.
Note
Before you proceed, make a backup copy of your VM, or take a snapshot of your OS disk.
Ubuntu
To increase the size of the OS disk in Ubuntu 16.x and 18.x:
- Stop the VM.
- Increase the size of the OS disk from the portal.
- Restart the VM, and then sign in to the VM as a root user.
- Verify that the OS disk now displays an increased file system size.
In the following example, the OS disk has been resized from the portal to 100 GB. The /dev/sda1 file system mounted on / now displays 97 GB.
user@myvm:~# df -Th
Filesystem Type Size Used Avail Use% Mounted on
udev devtmpfs 314M 0 314M 0% /dev
tmpfs tmpfs 65M 2.3M 63M 4% /run
/dev/sda1 ext4 97G 1.8G 95G 2% /
tmpfs tmpfs 324M 0 324M 0% /dev/shm
tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs tmpfs 324M 0 324M 0% /sys/fs/cgroup
/dev/sda15 vfat 105M 3.6M 101M 4% /boot/efi
/dev/sdb1 ext4 20G 44M 19G 1% /mnt
tmpfs tmpfs 65M 0 65M 0% /run/user/1000
user@myvm:~#
SUSE
To increase the size of the OS disk in SUSE 12 SP4, SUSE SLES 12 for SAP, SUSE SLES 15, and SUSE SLES 15 for SAP:
- Stop the VM.
- Increase the size of the OS disk from the portal.
- Restart the VM.
When the VM has restarted, complete these steps:
Access your VM as a root user by using this command:
# sudo -iUse the following command to install the growpart package, which you'll use to resize the partition:
# zypper install growpartUse the
lsblkcommand to find the partition mounted on the root of the file system (/). In this case, we see that partition 4 of device sda is mounted on /:# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 48G 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 512M 0 part /boot/efi ├─sda3 8:3 0 1G 0 part /boot └─sda4 8:4 0 28.5G 0 part / sdb 8:16 0 4G 0 disk └─sdb1 8:17 0 4G 0 part /mnt/resourceResize the required partition by using the
growpartcommand and the partition number determined in the preceding step:# growpart /dev/sda 4 CHANGED: partition=4 start=3151872 old: size=59762655 end=62914527 new: size=97511391 end=100663263Run the
lsblkcommand again to check whether the partition has been increased.The following output shows that the /dev/sda4 partition has been resized to 46.5 GB:
linux:~ # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 48G 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 512M 0 part /boot/efi ├─sda3 8:3 0 1G 0 part /boot └─sda4 8:4 0 46.5G 0 part / sdb 8:16 0 4G 0 disk └─sdb1 8:17 0 4G 0 part /mnt/resourceIdentify the type of file system on the OS disk by using the
lsblkcommand with the-fflag:linux:~ # lsblk -f NAME FSTYPE LABEL UUID MOUNTPOINT sda ├─sda1 ├─sda2 vfat EFI AC67-D22D /boot/efi ├─sda3 xfs BOOT 5731a128-db36-4899-b3d2-eb5ae8126188 /boot └─sda4 xfs ROOT 70f83359-c7f2-4409-bba5-37b07534af96 / sdb └─sdb1 ext4 8c4ca904-cd93-4939-b240-fb45401e2ec6 /mnt/resourceBased on the file system type, use the appropriate commands to resize the file system.
For xfs, use this command:
#xfs_growfs /Example output:
linux:~ # xfs_growfs / meta-data=/dev/sda4 isize=512 agcount=4, agsize=1867583 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0 spinodes=0 rmapbt=0 = reflink=0 data = bsize=4096 blocks=7470331, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal bsize=4096 blocks=3647, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 7470331 to 12188923For ext4, use this command:
#resize2fs /dev/sda4Verify the increased file system size for df -Th by using this command:
#df -ThlExample output:
linux:~ # df -Thl Filesystem Type Size Used Avail Use% Mounted on devtmpfs devtmpfs 445M 4.0K 445M 1% /dev tmpfs tmpfs 458M 0 458M 0% /dev/shm tmpfs tmpfs 458M 14M 445M 3% /run tmpfs tmpfs 458M 0 458M 0% /sys/fs/cgroup /dev/sda4 xfs 47G 2.2G 45G 5% / /dev/sda3 xfs 1014M 86M 929M 9% /boot /dev/sda2 vfat 512M 1.1M 511M 1% /boot/efi /dev/sdb1 ext4 3.9G 16M 3.7G 1% /mnt/resource tmpfs tmpfs 92M 0 92M 0% /run/user/1000 tmpfs tmpfs 92M 0 92M 0% /run/user/490In the preceding example, we can see that the file system size for the OS disk has been increased.
RHEL with LVM
Access your VM as a root user by using this command:
[root@dd-rhel7vm ~]# sudo -iUse the
lsblkcommand to determine which logical volume (LV) is mounted on the root of the file system (/). In this case, we see that rootvg-rootlv is mounted on /. If you want another file system, substitute the LV and mount point throughout this article.[root@dd-rhel7vm ~]# lsblk -f NAME FSTYPE LABEL UUID MOUNTPOINT fd0 sda ├─sda1 vfat C13D-C339 /boot/efi ├─sda2 xfs 8cc4c23c-fa7b-4a4d-bba8-4108b7ac0135 /boot ├─sda3 └─sda4 LVM2_member zx0Lio-2YsN-ukmz-BvAY-LCKb-kRU0-ReRBzh ├─rootvg-tmplv xfs 174c3c3a-9e65-409a-af59-5204a5c00550 /tmp ├─rootvg-usrlv xfs a48dbaac-75d4-4cf6-a5e6-dcd3ffed9af1 /usr ├─rootvg-optlv xfs 85fe8660-9acb-48b8-98aa-bf16f14b9587 /opt ├─rootvg-homelv xfs b22432b1-c905-492b-a27f-199c1a6497e7 /home ├─rootvg-varlv xfs 24ad0b4e-1b6b-45e7-9605-8aca02d20d22 /var └─rootvg-rootlv xfs 4f3e6f40-61bf-4866-a7ae-5c6a94675193 /Check whether there's free space in the LVM volume group (VG) that contains the root partition. If there is free space, skip to step 12.
[root@dd-rhel7vm ~]# vgdisplay rootvg --- Volume group --- VG Name rootvg System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 7 VG Access read/write VG Status resizable MAX LV 0 Cur LV 6 Open LV 6 Max PV 0 Cur PV 1 Act PV 1 VG Size <63.02 GiB PE Size 4.00 MiB Total PE 16132 Alloc PE / Size 6400 / 25.00 GiB Free PE / Size 9732 / <38.02 GiB VG UUID lPUfnV-3aYT-zDJJ-JaPX-L2d7-n8sL-A9AgJbIn this example, the line Free PE / Size shows that there's 38.02 GB free in the volume group. You don't need to resize the disk before you add space to the volume group.
To increase the size of the OS disk in RHEL 7.x with LVM:
- Stop the VM.
- Increase the size of the OS disk from the portal.
- Start the VM.
When the VM has restarted, complete the following step:
- Install the cloud-utils-growpart package to provide the growpart command, which is required to increase the size of the OS disk and the gdisk handler for GPT disk layouts. These packages are preinstalled on most marketplace images.
[root@dd-rhel7vm ~]# yum install cloud-utils-growpart gdiskDetermine which disk and partition holds the LVM physical volume or volumes (PV) in the volume group named rootvg by using the
pvscancommand. Note the size and free space listed between the brackets ([ and ]).[root@dd-rhel7vm ~]# pvscan PV /dev/sda4 VG rootvg lvm2 [<63.02 GiB / <38.02 GiB free]Verify the size of the partition by using
lsblk.[root@dd-rhel7vm ~]# lsblk /dev/sda4 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda4 8:4 0 63G 0 part ├─rootvg-tmplv 253:1 0 2G 0 lvm /tmp ├─rootvg-usrlv 253:2 0 10G 0 lvm /usr ├─rootvg-optlv 253:3 0 2G 0 lvm /opt ├─rootvg-homelv 253:4 0 1G 0 lvm /home ├─rootvg-varlv 253:5 0 8G 0 lvm /var └─rootvg-rootlv 253:6 0 2G 0 lvm /Expand the partition that contains this PV by using
growpart, the device name, and the partition number. Doing so will expand the specified partition to use all the free contiguous space on the device.[root@dd-rhel7vm ~]# growpart /dev/sda 4 CHANGED: partition=4 start=2054144 old: size=132161536 end=134215680 new: size=199272414 end=201326558Verify that the partition has resized to the expected size by using the
lsblkcommand again. Notice that in the example sda4 has changed from 63 GB to 95 GB.[root@dd-rhel7vm ~]# lsblk /dev/sda4 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda4 8:4 0 95G 0 part ├─rootvg-tmplv 253:1 0 2G 0 lvm /tmp ├─rootvg-usrlv 253:2 0 10G 0 lvm /usr ├─rootvg-optlv 253:3 0 2G 0 lvm /opt ├─rootvg-homelv 253:4 0 1G 0 lvm /home ├─rootvg-varlv 253:5 0 8G 0 lvm /var └─rootvg-rootlv 253:6 0 2G 0 lvm /Expand the PV to use the rest of the newly expanded partition:
[root@dd-rhel7vm ~]# pvresize /dev/sda4 Physical volume "/dev/sda4" changed 1 physical volume(s) resized or updated / 0 physical volume(s) not resizedVerify that the new size of the PV is the expected size, comparing it to the original [size / free] values:
[root@dd-rhel7vm ~]# pvscan PV /dev/sda4 VG rootvg lvm2 [<95.02 GiB / <70.02 GiB free]Expand the desired logical volume (LV) by the amount you want. The amount doesn't need to be all the free space in the volume group. In the following example, /dev/mapper/rootvg-rootlv is resized from 2 GB to 12 GB (an increase of 10 GB). This command will also resize the file system.
[root@dd-rhel7vm ~]# lvresize -r -L +10G /dev/mapper/rootvg-rootlvExample output:
[root@dd-rhel7vm ~]# lvresize -r -L +10G /dev/mapper/rootvg-rootlv Size of logical volume rootvg/rootlv changed from 2.00 GiB (512 extents) to 12.00 GiB (3072 extents). Logical volume rootvg/rootlv successfully resized. meta-data=/dev/mapper/rootvg-rootlv isize=512 agcount=4, agsize=131072 blks = sectsz=4096 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=4096 sunit=1 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 524288 to 3145728The
lvresizecommand automatically calls the appropriate resize command for the file system in the LV. Check whether /dev/mapper/rootvg-rootlv, which is mounted on /, has an increased file system size by using this command:[root@dd-rhel7vm ~]# df -Th /Example output:
[root@dd-rhel7vm ~]# df -Th / Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/rootvg-rootlv xfs 12G 71M 12G 1% / [root@dd-rhel7vm ~]#
Note
To use the same procedure to resize any other logical volume, change the LV name in step 12.
RHEL RAW
Note
Always take a snapshot of the VM before increasing OS disk size.
To increase the size of the OS disk in an RHEL RAW partition:
- Stop the VM.
- Increase the size of the OS disk from the portal.
- Start the VM.
When the VM has restarted, perform the following steps:
Access your VM as a root user by using the following command:
sudo suInstall the gptfdisk package, which is required to increase the size of the OS disk.
yum install gdisk -yTo see all the sectors available on the disk, run the following command:
gdisk -l /dev/sdaYou will see the details informing the partition type. Ensure it is GPT. Identify the root partition. Do not change or delete the boot partition (BIOS boot partition) and the system partition ('EFI System Partition')
Use the following command to start the partitioning for the first time.
gdisk /dev/sdaNow you will see a message asking for the next command ('Command: ? for help').
wYou will receive a warning stating "Warning! Secondary header is placed too early on the disk! Do you want to correct this problem? (Y/N):". You have to press 'Y'
YYou should see a message informing that final checks are complete and asking for confirmation. Press 'Y'
YCheck if everything happened correctly using partprobe command
partprobeThe above steps have ensured that the secondary GPT header is placed at the end. The next step is to start the process of resizing by using the gdisk tool again. Use the following command.
gdisk /dev/sdaIn the command menu, press 'p' to see list of partition. Identify the root partition (In the steps, sda2 is considered as the root partition) and the boot partition (In the steps, sda3 is considered as the boot partition)
p
Press 'd' to delete the partition and select the partition number assigned to boot (in this example it is '3')
d 3Press 'd' to delete the partition and select the partition number assigned to boot (in this example it is '2')
d 2
To recreate root partition with increased size, Press 'n', enter the partition number you deleted previously for root('2' for this example) and choose the First Sector as 'Default Value', Last Sector as 'Last sector value - boot size sector' ('4096 in this case' corresponding to 2MB boot) and Hex Code as '8300'
n 2 (Enter default) (Calculateed value of Last sector value - 4096) 8300To recreate boot partition, Press 'n', enter the partition number you deleted previously for boot('3' for this example) and choose the First Sector as 'Default Value', Last Sector as 'Default value' and Hex Code as 'EF02'
n 3 (Enter default) (Enter default) EF02Write the changes with the 'w' command and press 'Y' to confirm
w YRun command 'partprobe' to check for disk stability
partprobeReboot the VM and the root partition size would have been increased
reboot
Run the xfs_growfs command on the partition to resize it
xfs_growfs /dev/sda2
Verify the new size is reflected by using the df command:
[root@vm-dd-cent7 ~]# df -hl Filesystem Size Used Avail Use% Mounted on devtmpfs 452M 0 452M 0% /dev tmpfs 464M 0 464M 0% /dev/shm tmpfs 464M 6.8M 457M 2% /run tmpfs 464M 0 464M 0% /sys/fs/cgroup /dev/sda2 48G 2.1G 46G 5% / /dev/sda1 494M 65M 430M 13% /boot /dev/sda15 495M 12M 484M 3% /boot/efi /dev/sdb1 3.9G 16M 3.7G 1% /mnt/resource tmpfs 93M 0 93M 0% /run/user/1000