We’re excited to announce that it's now possible to share and attach a block storage volume to multiple compute instances on Oracle Cloud Infrastructure.
Up until now, although multiple block volumes can be attached to a single compute instance, there has been a limitation to attach a volume for read/write access from only one compute instance at a time. Other public cloud vendors have similar design limitations, with the exception of shared read-only volume access that is possible with some vendors.
With this announcement from Oracle Cloud Infrastructure, there is now an option to attach a volume with shareable, read/write access to multiple compute instances. This unique ability in cloud storage enables you to deploy and manage your cluster-aware solutions by using the shareable volumes provided by the Oracle Cloud Infrastructure Block Volumes service.
This feature by itself doesn’t handle coordination for concurrent writes from multiple compute instances. A separate cluster-aware system or solution is required and must be deployed on top of the shared storage provided by multiple-instance attachment. Some cluster-aware solutions that provide coordination for concurrent multiple writes are Oracle RAC (available and supported only via the Oracle Cloud Infrastructure Database service), Oracle Cluster File System (OCFS2), IBM Spectrum Scale (through our partnership with IBM), and GlusterFS.
For details about how to set up an example solution using multiple-instance attachment and OCFS2, see the Using the Multiple-Instance Attach Block Volume Feature to Create a Shared File System on Oracle Cloud Infrastructure blog post.
This new capability was primarily designed to support the Oracle Cloud Infrastructure Database service, which has been in production since May 2017. But we received significant demand to make it also publicly available. With this feature, you can continue to leverage the advantages of the highly available, durable, cost-effective, and elastic performant Block Volumes, and now also use it to create and manage your cluster-aware deployments and any solution that is designed to handle this capability.
A few example use cases:
This multiple-instance attachment capability was also key in enabling Oracle to achieve the IO500 benchmark top 15 list (see Oracle Cloud Joins the IO500 Fastest File Systems in the World).
By default, a volume is attached for nonshareable, exclusive read/write access from an instance with the same functionality that has always been available, unless the shareable read/write access option is selected for the first attachment to the volume. After a shareable attachment to the volume has been made, all subsequent attachments from different instances to the same volume are also shareable.
Additionally, we have extended all the read-only attachments to be shareable. When you attach a volume for read-only access, it’s enabled for shareable read-only attachment to multiple compute instances. You can share the contents of your shared block volume across multiple readers without a need for concurrency access control or a cluster-aware solution.
Sharing a block volume for read/write access is easy and seamless, with only a click on the Attach Block Volume page of the Console.
All the Block Volumes features—such as volume groups, deep disk-to-disk clones, and automated backups—still apply to the shareable volumes with multiple-instance attachment. You can adopt the multiple-instance attachment functionality for any of your existing or new detached volumes. If a volume hasn’t been attached for shareable read/write access before and you want it to be shareable, simply detach the volume and reattach it as a shareable volume. You also continue to experience the same Oracle Cloud Infrastructure Block Volume SLAs.
Shareable block volumes with multiple-instance attachment is available in all Oracle Cloud Infrastructure regions through the Oracle Cloud Infrastructure Console, CLI, SDK, and Terraform. For more information about this feature, see the Block Volumes documentation.
Watch for announcements in this space about more features and capabilities. We value your feedback as we continue to make our cloud service the best for enterprises. Send me your thoughts about how we can continue to improve our services or if you want more details about any topic.