AZ-104 Certification Notes

Chapter 10.3 - Disk Roles

Azure Disks - Disk Roles

There are 3 main disk roles in Azure, the data disk, the OS disk, the temporary disk. It's possible to see these three roles via remote accessing your VM.

• Data Disk
  • A managed disk that's attached to a virtual machine to store application data, or other data you need to keep
  • Registered as SCSI drives and are labeled with a letter that you choose
  • Has a maximum capacity of 32,767 gibibytes (GiB)
  • The size of the VM determines how many data disks you can attach and the type of storage you can use
• OS Disk
  • Every virtual machine has one attached operating system disk
  • The OS disk has a pre-installed OS, which was selected when the VM was created
  • This disk contains the boot volume
  • This disk has a maximum capacity of 4,095 GiB
• Temporary Disk
  • Most VMs contain a temporary disk, which is not a managed disk
  • Provides short-term storage for applications and processes, and is intended to only store data such as page or swap files
  • Data on the temporary disk may be lost during a maintenance event or when you redeploy a VM
  • During a successful standard reboot of the VM, data on the temporary disk will persist
  • The temporary disk is typically /dev/sdb on Linux and Windows VMs the temporary disk is D: by default
  • Not encrypted by SSE unless you enable encryption at host

Practice Quiz

• What are the three main disk roles in Azure?

  • Data disk
  • Temporary disk
  • Unique disk
  • OS disk

• What is a managed disk that's attached to a virtual machine to store application data, or other data you need to keep.

  • Data Disk

• Which disk role is a pre-installed OS, which is selected when a VM is created?

  • The OS Disk