Enable on-demand bursting
Premium solid-state drives (SSD) have two available bursting models; credit-based bursting and on-demand bursting. This article covers how to switch to on-demand bursting. Disks that use the on-demand model can burst beyond their original provisioned targets. On-demand bursting occurs as often as needed by the workload, up to the maximum burst target. On-demand bursting incurs additional charges.
For details on disk bursting, see Managed disk bursting.
For the max burst targets on each supported disk, see Scalability and performance targets for VM disks.
You don't need to follow the steps in this article to use credit-based bursting. By default, credit-based bursting is enabled on all eligible disks.
Before you enable on-demand bursting, understand the following:
- On-demand bursting cannot be enabled on a premium SSD that has less than or equal to 512 GiB. Premium SSDs less than or equal to 512 GiB will always use credit-based bursting.
- On-demand bursting is only supported on premium SSDs. If a premium SSD with on-demand bursting enabled is switched to another disk type, then disk bursting is disabled.
- On-demand bursting doesn't automatically disable itself when the performance tier is changed. If you want to change your performance tier but do not want to keep disk bursting, you must disable it.
- On-demand bursting can only be enabled when the disk is detached from a VM or when the VM is stopped. On-demand bursting can be disabled 12 hours after it has been enabled.
Currently, the on-demand model for disk bursting is available in all public Azure regions.
On-demand bursting can be enabled with either the Azure portal, the Azure PowerShell module, the Azure CLI, or Azure Resource Manager templates. The following examples cover how to create a new disk with on-demand bursting enabled and enabling on-demand bursting on existing disks.
A managed disk must be larger than 512 GiB to enable on-demand bursting.
To enable on-demand bursting for an existing disk:
- Sign in to the Azure portal and navigate to your disk.
- Select Configuration and select Enable on-demand bursting.
- Select Save.
To learn how to gain insight into your bursting resources, see Disk bursting metrics.