Organizations are changing how they run their businesses and many are looking to accelerate their move to the cloud to take advantage of the benefits that the cloud offers, including lower total cost of ownership (TCO) and improved flexibility and security, without sacrificing on performance, application compatibility, and availability. We are committed to delivering new innovations to help our customers easily migrate their business-critical applications to Azure.

Today, we are announcing the general availability of shared disks on Azure Disk Storage—enabling you to more easily migrate your existing on-premises Windows and Linux-based clustered environments to Azure. We are also announcing important new enhancements for Azure Disk Storage to provide you with more availability, security, and flexibility on Azure.

Azure shared disks general availability

With shared disks, Azure Disk Storage is the only shared block storage in the cloud that supports both Windows and Linux-based clustered or high-availability applications. This unique offering allows a single disk to be simultaneously attached and used from multiple virtual machines (VMs), enabling you to run your most demanding enterprise applications in the cloud, such as clustered databases, parallel file systems, persistent containers, and machine learning applications, without compromising on well-known deployment patterns for fast failover and high availability.

With Azure shared disks, partners can choose to leverage SCSI Persistent Reservations (PR) or STONITH Block Device (SBD) fencing models, consistent with their existing applications on-premises. With SCSI PR, you can use a well-known set of commands to choose from a range of supported access modes for one or more nodes to read or write to the disk. Partners can also leverage Azure shared disks as ReadWriteMany raw block devices for stateful Kubernetes applications like databases that want to avoid the overhead of a file system. With shared disks available on both Ultra Disks and Premium SSDs, partners can now build unique compelling offerings on Azure by leveraging a range of block storage options to optimize costs and performance.

Shared disks enable you to easily migrate the following applications to Azure:

  • SQL Server Failover Cluster Instances (FCI), Scale-out File Servers (SoFS), SAP ASCS/SCS running on Windows Server 2008+ (and beyond).
  • Linux applications running on GFS2, OCFS2, or distributed applications leveraging IO fencing on Linux including Red Hat Enterprise Linux High Availability (HA), SUSE Linux Enterprise HA and Ubuntu HA.

To get started with Azure shared disks, request access.

Since the preview announcement on February 13, 2020, we have seen strong adoption and great feedback from a wide range of customers and partners as shared disks enables mission- and business-critical workloads to be migrated to the cloud.

Below are a few quotes from participants in our preview program:

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“We have been waiting for shared disks in Azure since day one. Now we are able to deploy SQL Server Failover Clusters using Azure Virtual Machines and Azure Disk Storage. This allows us to easily migrate our High Availability workload from on-premises environments to the cloud with the added benefit of application compatibility.” —Javier Villegas, Global Database Administrator and Design Coordinator, MSC Technology


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“Azure shared disks enable us to accelerate the introduction of the Pure Cloud Block Store, an industry leading block storage offering for high scale enterprise workloads, disaster recovery, and test and development on Azure. With shared disks, we can provide a comprehensive high availability solution on Azure for our joint customers migrating their production applications and primary storage infrastructure to the cloud. Shared disks also allow us to simplify our product architecture and gives us the flexibility to provide a balanced price-performance option with a mix of Ultra Disks and Premium SSDs.” Kunal Kapoor, Director Product Management (Cloud Data Services)

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“Teradata Vantage provides a cloud-based analytics platform for mission-critical enterprise applications that require a highly available, resilient, and scalable architecture. Azure shared disks helps us reduce system recovery time by 70 percent, ultimately leading to a better customer experience and improved availability SLAs for our customers and also enables us to simplify our solution with comprehensive support for SCSI Persistent Reservations. By supporting a range of disk types, it also allows us to offer different performance options to our customers to meet their varying workload requirements and business needs.” Eleni Rundle, Vice President of Product Engineering, Cloud and Applications, Teradata

Shared disks types, sizes, and pricing

Shared disks are available on Ultra Disks and Premium SSDs (disks larger than P15) and can only be enabled as data disks (not OS disks). On Premium SSDs, each additional mount to a shared disk is charged a mount fee that depends on the disk size. For Ultra Disks, there is no charge per mount; you are charged for the capacity, total IOPS, and total throughput on the disk. Please refer to the Azure Disks pricing page for details on general availability pricing.

In addition to enabling new block storage workloads to migrate to the cloud with shared disks, we are also introducing new enhancements for  Azure Disk Storage that will improve the availability, security, and flexibility of workloads running on Azure.

Improved availability guarantees with single VM SLA for Standard SSD and Standard HDD

To strengthen the availability guarantee of our VMs, we are extending the single-instance VM SLA to all disk types including Standard SSD and Standard HDD. Previously, we offered an SLA of 99.9 percent for single-instance VMs using Premium SSD and Ultra Disks..

We now offer an SLA of 99.5 percent for single-instance VMs using Standard SSD and an SLA of 95 percent for single-instance VMs using Standard HDD, improving our availability guarantee to cover all single-instance VMs. With this SLA update, Azure provides an industry-leading availability guarantee for VMs leveraging SSD disk options in production.

Export and import your data securely over a private virtual network with Azure Private Links integration (preview)

Using a time-bound shared access signature (SAS) uniform resource identifier (URI), Azure Disk Storage provides you the flexibility to securely upload data from virtual hard disks (VHD) on-premises or export data from an unattached disk or snapshots for cross region copy, disaster recovery, and forensic analysis. For enhanced security, you can now restrict access to your data by only allowing import and export from your private Azure virtual network by leveraging the integration with Azure Private Link. Get started today by checking out the documentation.

Achieve higher performance and cost savings with performance tiers (preview)

Azure Disk Storage currently offers built-in bursting capabilities on Lsv2-series VMs and small Premium SSDs (P1 to P20) to achieve higher performance for handling short-term unexpected traffic. For an event like Black Friday, performance testing, running a training environment, you need to achieve consistently higher performance for a few days or hours and then return to the normal performance levels. On Premium SSDs, you now have the flexibility to increase the disk performance without increasing the disk size and come back to baseline performance, allowing you to match workload performance needs and reduce costs.

A baseline performance tier is set based on your provisioned disk size. You can set a higher performance tier when your application requires this to meet higher demand and return to the initial baseline performance tier once this period is complete. For example, if you provision a P10 disk (128 GB), your baseline performance tier is set as P10 (500 IOPS and 100 MB/s). You can update the tier to match the performance of P50 (7500 IOPS and 250 MB/s) without increasing the disk size and return to P10 when higher performance is no longer needed. Please sign up for access to our private preview.

Get started

To get started with shared disks, please refer to the shared disk documentation page. For updates on shared disks regional availability and Ultra Disk availability, please refer to the Azure Disks FAQs. In the coming weeks, we will be enabling portal support. Support for Azure Backup and Azure Site Recovery is currently not available. Refer to the Azure Disks documentation for detailed instructions on all disk operations. Please email us at to share your feedback, or leave a comment in the Azure Storage feedback forum.