Extend a persistent volume

You are able to extend volumes to create more space available on your compute instances.

This is good because you do not have to pay for space that you are not sure if you are going to need or not, from when setting up the instance and can start small.

Caution

While you can extent a volume, you cannot revert an extension or decrease the size of a volume. If you need a smaller volume, create a new volume and migrate the data.

Important

Manipulating the partition table of disks is always a dangerous process. We strongly recommend first backing up your instances disks before proceeding.

Cloud management portal

To extend a volume by using the Cloud management portal

  • Press Compute and then Instances.

  • Press the instance having the volume you want to extend.

  • Press the Volumes tab. It might require scrolling the tabs to the right.

  • Press the name of the volume that you want to extend.

  • Press the Extend volume button (to the top right, looks like a dotted square).

  • Enter the new size in GB and press Extend.

OpenStack Horizon

To extend a volume by using OpenStack Horizon

  • Under Project, press Compute and then Instances in the sidebar menu.

  • Press the instance having the volume you want to extend.

  • Press the name of the volume under the Volumes Attached section.

  • Press the dropdown next to Edit volume on the top right and select Extend volume

  • Enter the new size in GB and press Extend Volume

OpenStack Terminal Client

To extend a volume by using the OpenStack Terminal Client

  • Run this command: openstack server list, save the name of the instance having the volume you want to extend.

  • Run this command: openstack server volume list [NAME_OF_INSTANCE], replacing the name with that from previous step.

  • Find the volume you want to extend and copy the volume ID.

Note

Use 3.42 microversion or newer for the Cinder API as that introduced support for extending an in-use volume.

  • Run this command: openstack --os-volume-api-version 3.42 volume set [VOLUME_ID] --size [SIZE], replacing the values in angle brackets with the volume ID from the previous step and the size in GB.

  • To verify, run this command: openstack volume show [VOLUME_ID] -c size, replacing value with the volume ID.

Operation inside operating system

Above we walked through the process for growing a volume in the platform but there is also a need to grow the disk and file system inside the instance.

Depending on what operating system you are running this process will vary and below are just suggestions that we have found to be useful.

For a complete reference, see your operating systems documentation.

Important

Manipulating the partition table of disks is always a dangerous process. We strongly recommend first backing up your instances disks before proceeding.

Linux

  • Run this command: lsblk, verify that the new disk size is visible on the device. If its not, reboot your machine and try again.

  • Run this command: growpart -u auto /dev/sda 1, use the correct device (/dev/sda in the example) from previous commands output. This might not work on all images, if not then we recommend reading the documentation of your Linux distribution.

  • Run this command: resize2fs /dev/sda1.

  • To verify, run this command: df -h /dev/sda1.

Windows

  • Type Computer Management in the search box on the taskbar, select and hold (or right-click) Computer Management, and then select Run as administrator > Yes. After Computer Management opens, go to Storage > Disk Management.

  • Select and hold (or right-click) the volume that you want to extend, and then select Extend Volume.

See also