Exploring ephemeral OS disks

In a standard scenario (no additional performance requirements, OS disk data persistence), you can use a typical OS disk that will be provisioned as a managed disk stored on a remote Azure Storage account. This simplifies setup and management but will also impact the latency of the input/output operations per second (IOPS) of a disk. If you’re looking for improved performance, Azure offers ephemeral OS disks, which are configured and managed differently.

An ephemeral OS disk is provisioned directly on a machine. This means that they’re collocated with your virtual machine, giving some boost to the latency of disk operations. They also have some additional traits:

• No additional cost – ephemeral disks are free because they don’t use Azure Storage.
• Not all virtual machine families support them.
• The maximum size depends on the maximum size of the temporary disk of the virtual machine cache. In general, they cannot...