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VM Resize

Changing the size of a server affects the resources (CPU, RAM and hard disk) available to that server. For ccloud³ VMs, there are two options for resizing:

  1. CPU and RAM only: This option allows you to change the amount of CPU and RAM available to a ccloud³ VM.
  2. Hard disk, CPU and RAM: This option allows you to change the amount of CPU and RAM available to a ccloud³ VM and to permanently increase the size of the ccloud³ VM’s hard disk.

Increasing the RAM and CPU of a ccloud³ VM improves its performance. Increasing the hard disk capacity increases the amount of data you can store.

You can upgrade to any ccloud³ VM plan that offers the same amount of hard disk space as your original ccloud³ VM, or more. This means you can increase or decrease the amount of CPU and RAM, whilst increasing the amount of hard disk space.

Requirements​

Things to consider before resizing​

  • Allow for approximately one minute of downtime per GB of hard disk space used, although the time actually required is usually shorter. You can check the hard disk space in the file system using df / -h.
  • The estimated downtime depends on disk usage, even for resizing operations that do not change the disk size. This is because the ccloud³ VM may migrate to a new hypervisor, which involves transferring disk data over the network.
  • We strongly recommend creating a snapshot of the ccloud³ VM before resizing.
  • ccloud³ VMs may switch hypervisors during a resize, and changes to the file system may result in data loss if problems occur. We strongly recommend that you back up the data on the ccloud³ VM before resizing it. If you use snapshots, you can delete the snapshot once you have confirmed that the migration has been successful.
  • You cannot reduce the hard disk size of a ccloud³ VM.

Modifying ccloud³ VMs via the Control Panel or the API​

  • You can modify ccloud³ VMs via the Control Panel or the centron API.
  • Before you can modify a ccloud³ VM in the Control Panel, you must shut it down. We recommend doing this via the command line to avoid data corruption. SSH into your ccloud³ VM and run the sudo shutdown -h now command.
  • Then go to the centron Control Panel. On the ccloud³ VMs page, click the name of the ccloud³ VM you wish to modify, and then click the ‘Resize’ option in the ccloud³ VM-specific menu.
  • Select either ‘CPU and RAM only’ or ‘Hard disk, CPU and RAM’ for resizing, then choose the new ccloud³ VM size. Once the ccloud³ VM has shut down and you have selected its new plan, click ‘Resize’. A progress bar will show the progress of the resizing.
  • Once the resizing is complete, click the power button to switch the ccloud³ VM back on.

Checking changes to hard disk sizes​

  • In certain cases, a disk resize operation to change the partition or file system of the ccloud³ VM may fail. If you run df -h again after a disk resize and the output remains unchanged, this usually indicates a problem. Use gdisk to obtain further information.
  • To change the partition, use the growpart command.
  • The command for changing the file system depends on the file system type. Use resize2fs for ext3/4 file systems or xfs_growfs for XFS file systems.
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