Ephemeral OS Disk in limited preview
Last week at Microsoft Ignite, we launched Ultra SSD, a new industry leading high-performance disk type for IO intensive workloads. Adding to that, today we are delighted to share the limited preview of Ephemeral OS Disk, a new type of OS disk created directly on the host node, providing local disk performance and faster boot/reset time.
Ephemeral OS Disk is supported for all virtual machines (VM) and virtual machine scale sets (VMSS). This offering is based on your feedback to provide a lower cost, higher performant OS disk for stateless applications, which enable them to quickly deploy the VMs and reset them to its original state.
Ephemeral OS Disk is ideal for stateless workloads that require consistent read/write latency to OS disk, as well as frequent reimage operations to reset the VM(s) to the original state. This includes workloads such as website applications, game server hosting services, VM pools, computation, jobs and more. Ephemeral OS Disk also works well for workloads that are leveraging low-priority VM scale sets.
Key comparisons between Persistent OS disk and Ephemeral OS disk
|Persistent OS Disk||Ephemeral OS Disk|
|Size limit for OS disk||2 TiB||
Up to 30 GiB for preview
Up to VM cache size at general availability
|VM sizes supported||All||DSv1, DSv2, DSv3, Esv2, Fs, FsV2, GS|
|Disk type support||Managed and unmanaged OS disk||Managed OS disk only|
|Region support||All regions||All regions excluding sovereign clouds|
|Specialized OS disk support||Yes||No|
|Data persistence||OS disk data written to OS disk are stored in Azure Storage||OS disk data is stored to local host machine and is not persisted to Azure Storage|
|Stop-deallocated state||VMSS instances and VMs can be stop-deallocated and restarted from the stop-deallocated state||VMSS instances and VMs cannot be stop-deallocated|
|OS disk resize||Supported during VM creation and after VM is stop-deallocated||Supported during VM creation only|
|Resizing to a new VM size||OS disk data is preserved||OS disk data is deleted, OS is re-provisioned|
How to join preview
To enroll in the limited public preview, you will need to submit this form and your subscription will be approved within 24 to 48 hours starting October 10, 2018. You can check the status of your request by running the following PowerShell command:
Get-AzureRmProviderFeature -FeatureName localdiffdiskpreview -ProviderNamespace Microsoft.Compute