Block Volume Storage Overview

8 Block Volume Storage Overview

Block Volumes provide high-performance network storage capacity that supports a broad range of I/O intensive workloads.

You can use block volumes to expand the storage capacity of your compute instances, to provide durable and persistent data storage that can be migrated across compute instances, and to host large databases.

The Block Volume service enables you to group multiple volumes in a volume group. Volume groups simplify the process to create backups and clones. For more information, see Block Volume Groups.

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

Types of Block Volumes

There are two types of volumes:

Boot volume: A detachable boot volume device that contains the image that is used to boot a Compute instance. See Boot Volumes.
Block volume: A detachable block storage device that allows you to dynamically expand the storage capacity of an instance.

The default size for both types of volumes is 50 GB.

You can create, attach, connect, and move volumes, as well as change volume performance to meet your storage, performance, and application requirements.

After you attach and connect a volume to a compute instance, you can use the volume like a regular hard drive. You can also disconnect a volume and attach it to another compute instance without the loss of data.

Required Components

These components are required to create a volume and attach it to a compute instance:

Compute Instance: A virtual machine (VM) running in the cloud appliance.
Volume attachment: A paravirtualized attachment that is available for compute instances.
Volume: A block volume or boot volume.

Block Volume Performance Options

Elastic Performance

When you configure block storage, you can select one of these block storage types:

High performance: The Higher Performance elastic performance option is recommended for workloads with the highest I/O requirements, requiring the best possible performance, such as large databases.
Balanced performance: Suitable for most applications including boot volumes.

This performance option provides a good balance between performance and cost savings for most workloads, including workloads that perform random I/O such as boot volumes.

Performance Limitations and Considerations

The following performance results are for unformatted data volumes.

Throughput performance on compute instances depends on the network bandwidth that is available to the compute instance, and further limited by that bandwidth for the volume.
If Microsoft Defender Advanced Threat Protection (Microsoft Defender ATP) is enabled in an instance, it has a significant negative impact on disk I/O performance. However, carefully consider the security implications of disabling Microsoft Defender ATP.
Block volume performance is per volume, so when a block volume is attached to multiple compute instances, the performance is shared across all the attached compute instances.

You can change a volume's performance setting anytime by editing the volume. Refer to the Block Volume Storage in the Oracle Private Cloud Appliance User Guide.

Block Volume Scenarios

Adding Storage Capacity

A common use of a block volume is to add storage capacity to an instance. After you launch an instance and set up your cloud network, you can create a block storage volume. Then, you attach the volume to a compute instance using a volume attachment. The volume can then be mounted and used by your compute instance.

Moving a Volume to Another Compute Instance

A block volume can be detached from a compute instance and moved to a different compute instance without the loss of data. This data persistence enables you to migrate data between compute instances and ensures that your data is safely stored, even when it is not connected to a compute instance. Any data remains intact until you delete the volume.

To move your volume to another compute instance, unmount the drive from the initial compute instance, detach the block volume, then attach the volume to another compute instance. From there, you connect and mount the drive from that instance's guest OS to have access to the data.

Scaling a Compute Instance

When you terminate a compute instance, you can keep the associated boot volume and use it to launch a new compute instance with a different compute instance type or shape. This capability enables you to easily scale up or scale down the number of cores for a compute instance.

Block Volume Groups

The Block Volume service enables you to group multiple volumes in a volume group.

A volume group can include both types of volumes:

Boot Volumes: The system disks for compute instances
Block Volumes: Volumes for data storage

You can use volume groups to create volume group backups and clones that are point-in-time and crash-consistent.

This simplifies the process to create time-consistent backups of running enterprise applications that span multiple storage volumes across multiple compute instances. You can then restore an entire group of volumes from a volume group backup.

Note:

You can also clone an entire volume group in a time-consistent and crash-consistent manner. A deep disk-to-disk and fully isolated clone of a volume group, with all the volumes associated in it, becomes available for use within a matter of seconds. This action speeds up the process of creating environments for development, quality assurance, user acceptance testing, and troubleshooting.

This capability is available using the Compute Web UI, CLI, or API.

Volume groups and volume group backups are high-level constructs that allow you to group multiple volumes. When working with volume groups and volume group backups, keep the following points in mind:

You can only add a volume to a volume group when the volume status is available.
You can add up to 32 volumes in a volume group. The maximum Block Volumes aggregated size is 100 TB.
Each volume can only be in one volume group.
When you clone a volume group, a new group with new volumes are created. For example, if you clone a volume group containing three volumes, after this operation is complete, you have two separate volume groups and six different volumes with nothing shared between the volume groups.
When you update a volume group using the CLI or API, you need to specify all the volumes to include in the volume group each time you use the update operation. If you do not include a volume ID in the update call, that volume is removed from the volume group.
When you delete a volume group, the individual volumes in the group are not deleted, only the volume group is deleted.
When you delete a volume that is part of a volume group, you must first remove it from the volume group before you can delete it.
When you delete a volume group backup, all the volume backups in the volume group backup are deleted.

Volume Backups and Clones

Backup and Restore

Backup and restore activities are supported on boot volumes, data volumes, and volume groups.

To back up a boot volume, you can create a manual backup or clone the boot volume. See Cloning a Boot Volume.

There are two backup methods for block volumes and volume groups:

Manual backups: You manually perform create, get, list, rename, and delete backup commands.
Automatic backups: You create a backup policy and a backup policy assignment that specifies the time and frequency of the volume backups. The system automatically performs the commands that back up the volume.

Volume Group Back Up and Restore

You can perform most of the same backup operations and tasks with volume groups that you can perform with individual block volumes.

Volume group backups enable you to manage the backup settings for several volumes in one place. This feature simplifies the process to create time-consistent backups of running enterprise applications that span multiple storage volumes across multiple compute instances.

You can restore a volume group backup to a volume group, or you can restore individual volumes in the volume group from volume backups.

Clones

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

The clone operation occurs immediately, and you can attach and use the cloned volume as a regular volume when the state changes to available. At this point, the volume data is being copied in the background, and can take up to thirty minutes depending on the size of the volume.

There is a single point-in-time reference for a source volume while it is being cloned. If the source volume is attached when a clone is created, you need to wait for the first clone operation to complete from the source volume before creating additional clones. If the source volume is detached, you can create up to 10 clones from the same source volume simultaneously.

You can only create a clone for a volume within the same tenant. You can create a clone for a volume between compartments as long as you have the required access permissions for the operation.

Differences Between Volume Clones and Backups

Consider the following criteria when you decide whether to create a backup or a clone of a volume.

Comparison	Volume Backup	Volume Clone
Description	Creates a point-in-time backup of data on a volume. You can restore multiple new volumes from the backup later in the future.	Creates an immediately usable copy of a block volume without having to go through the backup and restore process.
Use Case	Retain a backup of the data in a volume, so that you can duplicate an environment later or preserve the data for future use. Meet compliance and regulatory requirements, because the data in a backup remains unchanged over time. Support business continuity requirements. Reduce the risk of outages or data mutation over time.	Creates an immediately usable copy of a block volume without having to go through the backup and restore process.
Storage Location	Block Volume	Block Volume
Retention Policy	Policy-based backups expire, manual backups do not expire.	No expiration
Volume Groups	Supported. You can back up a volume group.	Supported. You can clone a volume group.