Boot Volumes

When you launch a virtual machine (VM) or bare metal instance based on an Oracle-provided image or custom image, a new boot volume for the instance is created in the same compartment. That boot volume is associated with that instance until you terminate the instance. When you terminate the instance, you can preserve the boot volume and its data. For more information, see Terminating an Instance. This feature gives you more control and management options for your compute instance boot volumes, and enables:

  • Instance scaling: When you terminate your instance, you can keep the associated boot volume and use it to launch a new instance using a different instance type or shape. See Creating an Instance for steps to launch an instance based on a boot volume. This allows you to switch easily from a bare metal instance to a VM instance and vice versa, or scale up or down the number of cores for an instance.
  • Troubleshooting and repair: If you think a boot volume issue is causing a compute instance problem, you can stop the instance and detach the boot volume. Then you can attach it to another instance as a data volume to troubleshoot it. After resolving the issue, you can then reattach it to the original instance or use it to launch a new instance.

Boot volumes are encrypted by default, the same as other block storage volumes. For more information, see Block Volume Encryption.

Important

In-transit encryption for boot and block volumes is only available for virtual machine (VM) instances launched from Oracle-provided images, it is not supported on bare metal instances. It is also not supported in most cases for instances launched from custom images imported for "bring your own image" (BYOI) scenarios. To confirm support for certain Linux-based custom images and for more information contact Oracle support, see Getting Help and Contacting Support.

You can group boot volumes with block volumes into the same volume group, making it easy to create a group volume backup or a clone of your entire instance, including both the system disk and storage disks at the same time. See Volume Groups for more information.

You can move Block Volume resources such as boot volumes and boot volume backups between compartments. For more information, see Move Block Volume Resources Between Compartments.

For more information about the Block Volume service and boot volumes, see the Block Volume FAQ.

Custom Boot Volume Sizes

When you launch an instance, you can choose whether to use the selected image's default boot volume size, or to specify a custom size up to 32 TB. This capability is available for the following image source options:

  • Oracle-provided image

  • Custom image

  • Image OCID

See Creating an Instance for more information.

For Linux-based images, the custom boot volume size must be larger than the image's default boot volume size or 50 GB, whichever is higher.

For Windows-based images, the custom boot volume size must be larger than the image's default boot volume size or 256 GB, whichever is higher. The minimum size requirement for Windows images is to ensure that there is enough space available for Windows patches and updates that can require a large amount of space, to improve performance, and to provide adequate space for setting a suitable page file (see this Microsoft known issue for page file settings on Windows Server 2012 R2).

After you launch an instance, you can't change the boot volume size.

If you specify a custom boot volume size, you need to extend the volume to take advantage of the larger size. For steps, see Extending the Partition for a Boot Volume.

Boot Volume Performance

Boot volume performance varies with volume size, see Block Volume Performance for more information.

The Block Volume service's elastic performance feature enables you to dynamically change the volume performance for boot volumes. Once an instance has been created, you can change the volume performance of the boot volume to one of the following performance options:

  • Balanced

  • Higher Performance

For more information about this feature and the performance options, see Block Volume Elastic Performance and Changing the Performance of a Volume

Required IAM Service Policy

To use Oracle Cloud Infrastructure, you must be given the required type of access in a policy  written by an administrator, whether you're using the Console or the REST API with an SDK, CLI, or other tool. If you try to perform an action and get a message that you don’t have permission or are unauthorized, confirm with your administrator the type of access you've been granted and which compartment  you should work in.

For administrators: The policy in Let users launch Compute instances includes the ability to list boot volumes. The policy in Let volume admins manage block volumes, backups, and volume groups lets the specified group do everything with block volumes, boot volumes, and backups, but not launch instances.

If you're new to policies, see Getting Started with Policies and Common Policies. For reference material about writing policies for instances, cloud networks, or other Core Services API resources, see Details for the Core Services.