A virtual machine uses three types of disks, they are:
Operating System Disk: It is created along with the virtual machine by Azure. It is generally mounted as C drive, which is 2 GB in size.
Temporary Disk: This disk holds temporary contents, although, you are not suggested to store anything there. If the VM is redeployed for any reason, the drive is wiped out and starts fresh. The primary function of that temporary disk is simply for the page file.
Data Disk stores all the data required to be worked upon. This disk is huge and has high performance.
Data Disks on VMs
So, apart from all the disks, the Data disks are crucial. Want to know how and why? Check out.
Data Disks are where the working data and all the application data reside. The size of VM decides the number of data disks that can be attached to a VM. Data disks are stored in a BLOB in an Azure storage account.
Data disks could be of type Standard or Premium, both of which may be again managed or unmanaged.
Standard storage uses HDDs with a maximum IOPS (I/O Operations per second) of 50000 and the number of disks up to 100 (each disk is of 4 GB).
Premium storage has an unlimited IOPS and has 35 TB of storage and 10 TB of snapshots.