We introduced the preview of bursting support on Azure Premium SSD Disks, and new disk sizes 4/8/16 GiB on both Premium & Standard SSDs at Microsoft Ignite in November. We would like to share more details about it. With bursting, eligible Premium SSD disks can now achieve up to 30x of the provisioned performance target, better handling for spiky workloads. If you have workloads running on-premises with less predictable disk traffic, you can migrate to Azure and improve your overall performance taking advantage of bursting support.

Disk bursting is enforced on a credit based system, where you will accumulate credits when traffic is below provisioned target and consume credit when it exceeds provisioned. You can best leverage the capability in these scenarios below:

• OS disks to accelerate virtual machine (VM) boot: You can expect to experience a boost as part of VM boot where reads to the OS disk may be issued at a higher rate. If you are hosting cloud workstations on Azure, your applications launch time can potentially be reduced taking advantage of additional disk throughput.
• Data disks to accommodate spiky traffic: Some production operations trigger spikes of disk input/output (IO) by design. For example, if you conduct a database checkpoint, there will be a sudden increase of writes against the data disk, and a similar increase in reads for backup operations. Disk bursting provides you better flexibility to handle any excepted or unexpected change of disk traffic pattern.

With this preview release, we lower the entry cost of cloud adoption with smaller disk sizes and make our disk offerings more performant leveraging burst support. Start leveraging these new disk capabilities to build your most performant, robust and cost-efficient solution on Azure today!

Getting Started

Create new managed disks on the burst applicable sizes using the Azure portal, Powershell, or command-line interface (CLI) now! You can find the specifications of burst eligible and new disk sizes in the table below. The preview regions that support bursting and new disk sizes are listed in our Azure Disks frequently asked questions article. We are actively extending the preview support to more regions.

Premium SSD managed disks

Bursting capability is supported on Premium SSD managed disks only. It will be enabled by default for all new deployments in the supported regions. For existing disks of the applicable sizes, you can enable bursting with either of the two options: detach and re-attach the disk or stop and restart the attached VM. To learn more details on how bursting works, please refer to this “What disk types are available in Azure?” article.

Standard SSD Managed Disks

Here are the new disk sizes introduced on Standard SSD Disks. The performance targets define the max IOPS and bandwidth you can achieve on these sizes. Compared to Premium SSD Disks above, the disk IOPS and bandwidth offered are not provisioned. For your performance sensitive workloads or single instance deployment, we recommend you leverage Premium SSDs.

Visit our service website to explore the Azure Disk Storage portfolio. To learn about pricing, you can visit the Azure Managed Disks pricing page.

General feedback

We look forward to hearing your feedback on the new disk sizes. Please email us at AzureDisks@microsoft.com.