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VM Resize

Changing the size of a server affects the resources (CPU, RAM and hard disk) available to it. 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.

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

Prerequisites​

Things to consider before resizing​

  • Allow for about 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 hard disk usage – even in the case of resizing operations that do not change the hard disk size. This is because the ccloud³ VM may be migrated to a new hypervisor, which involves transferring hard disk data over the network.

  • We strongly recommend that you take a snapshot of the ccloud³ VM before resizing it.

  • ccloud³ VMs can switch hypervisors during resizing. 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 are using snapshots, you can delete the snapshot once you have confirmed that the migration has been successful.

  • You cannot reduce the size of the hard disk on a ccloud³ VM.

Modifying ccloud³ VMs via the Control Panel or the API​

  • You can modify ccloud³ VMs via Control Panel or the centron API.

  • Before you can make changes to a ccloud³ VM in the Control Panel, you must shut it down. We recommend doing this via the command line to avoid data corruption. Add SSH to your ccloud³ VM and run the sudo shutdown -h now command.

  • Next, go to centron Control Panel. On the ccloud³ VMs page, click the name of the ccloud³ VM you wish to modify, then click the ‘Resize’ option in the ccloud³ VM-specific menu.

  • Select ‘CPU & RAM’ or ‘Hard Disk, CPU & RAM’ to resize, then choose the desired ccloud³ VM size. Once the ccloud³ VM has shut down and you have selected your new plan, click ‘Resize’. A progress bar will show the progress of the resizing process.

  • Once the resizing is complete, click the power button to switch the ccloud³ VM back on.

Checking changes to hard drive sizes​

  • In certain cases, resizing the hard disk to change the partition or file system of the ccloud³ VM may fail. If you run df / -h again after resizing the hard disk 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 type of file system. Use resize2fs for ext3/4 file systems or xfs_growfs for XFS file systems.

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