1. Concepts Guide
  2. Compute Instance Concepts
  3. Boot Volumes

Boot Volumes

When you launch a compute instance based on an Oracle platform image or custom image, a new boot volume for the compute instance is created in the same compartment. That boot volume is associated with that compute instance until you terminate the compute instance.

When you terminate the compute instance, you can preserve the boot volume and its data. This feature gives you more control and management options for your compute instance boot volumes, and enables:

  • Instance scaling: When you terminate your compute instance, you can keep the associated boot volume and use it to launch a new compute instance using a different compute instance type or shape. This flexibility enables you to easily scale up or down the number of cores for a compute instance.

  • Troubleshooting and repair: If you think a boot volume issue is causing a compute instance problem, you can stop the compute instance and detach the boot volume. Then you can attach it to another compute instance as a data volume to troubleshoot it. After resolving the issue, you can then reattach it to the original compute instance or use it to launch a new compute instance.

Boot volume Encryption

Boot volumes are encrypted by default, the same as other block storage volumes.

Important:

Usually, encryption is not supported for compute instances launched from custom images imported for "bring your own image" (BYOI) scenarios.

Listing Boot Volumes

You can list all boot volumes in a specific compartment, or list detailed information on a single boot volume.

Listing Boot Volume Attachments

You can list all the boot volume attachments in a specific compartment. You can also view detailed information on a single boot volume attachment.

Detaching and Attaching a Boot Volume

If a boot volume has been detached from the associated compute instance, you can reattach it to the compute instance. If you want to restart a compute instance with a detached boot volume, you must reattach the boot volume.

If you think a boot volume issue is causing a compute instance problem, you can stop the compute instance and detach the boot volume. Then you can attach it to another compute instance as a data volume to troubleshoot it.

If a boot volume has been detached from the associated compute instance, or if the compute instance is stopped or terminated, you can attach the boot volume to another compute instance as a data volume.

Extending a Boot Volume Partition

You can extend the partition for a boot volume for an existing compute instance by resizing a volume. To take advantage of the larger size, you also need to extend the partition for the boot volume.

Deleting a Boot Volume

When you terminate a compute instance, you choose to delete or preserve the associated boot volume.

If a boot volume has been detached from the compute instance, you can delete the boot volume.

For step-by-step instructions for managing boot volumes, refer to the Block Volume Storage chapter in the Oracle Private Cloud Appliance User Guide.

Custom Boot Volume Sizes

When you launch a compute instance, you can accept the image's default boot volume size, or you can specify a custom size up to 16 TB.

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 Microsoft 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 Microsoft Windows images is to ensure that enough space is available for patches and updates.

If you specify a custom boot volume size, extend the volume to take advantage of the larger size.

Boot Volume Backups

The backups feature of the Block Volume service lets you make a crash-consistent backup, which is a point-in-time snapshot of a boot volume without application interruption or downtime. You can make a backup of a boot volume while it is attached to a running compute instance, or while it is detached from the compute instance. The backup is a full backup.

You can restore a boot volume from any of your boot volume backups. You only need to keep the backups taken for the times you care about.

Boot Volume Tags

When a boot volume backup is created, the source boot volume's tags are automatically included in the boot volume backup.

When you create a compute instance from the boot volume backup, the compute instance includes the source boot volume's tags.

Boot Volume Backup Size

The boot volume backup size might be larger than the source boot volume size for the following reasons:

  • Any part of the boot volume that has been written to is included in the boot volume backup.

  • Many operating systems write or zero out the content, which results in these blocks marked as used. The Block Volume service considers these blocks updated and includes them in the volume backup.

  • Boot volume backups also include metadata, which can be up to 1 GB in additional data.

Restoring a Boot Volume

You can use a boot volume backup to create a compute instance or you can attach it to another compute instance as a data volume. However before you can use a boot volume backup, you need to restore it to a boot volume.

You can restore a boot volume from any of your boot volume backups. You only need to keep the backups taken for the times you care about.

Cloning a Boot Volume

You can create a clone from a boot volume using the Block Volume service. Cloning enables you to make a copy of an existing boot volume without needing to go through the backup and restore process.

Any subsequent changes to the data on the source boot volume are not copied to the boot volume clone. The clone is the same size as the source boot volume unless you specify a larger volume size when you create the clone.

The clone operation occurs immediately and you can use the cloned boot volume when the state changes to available.

There is a single point-in-time reference for a source boot volume while it is being cloned. If you clone a boot volume while the associated compute instance is running, you need to wait for the first clone operation to complete before creating more clones. You also need to wait for any backup operations to complete.

You can only create a clone for a boot volume within the same tenant. You can create a clone of a boot volume in a different compartment from the source volume compartment if you have the required access permissions.