Learning Microsoft Azure Storage

Sparse storage and TRIM in Azure

When you create a VHD on Azure to store your data on it, all the space you have chosen as a size for your VHD is completely allocated because Azure uses fixed-size VHDs. Therefore, you may wonder, will I really pay for the whole space even if I’m not using it, especially as it is not a dynamic disk but a fixed one.

Let's discuss this in more detail.

When you create a VHD, all the size is allocated, and that might trick you into using smaller VHDs to save costs, but actually that is not what really happens behind the scenes.

Azure uses sparse storage, which means no matter the size of the VHD you have created, you will only pay for what you have stored on the VHD. For example, you have a 1 TB VHD, but you have ...