Azure Classroom Series – 09/Nov/2021

Azure Managed Disks

• Azure managed disks are block-level storage volumes that are managed by Azure & used with Azure VMs
• The types of managed disks are
  • ultra disks
  • Premium state SSD (Solid State Disks)
  • Standard SSD
  • Standard Hard disk Drives
• Refer Here for the disk type comparison and also refer each disk type for the IOPS as per the size.
• In Azure, when we create a VM, a physical server is allocated on which vm is created
  • OS Disk will be created but from a different physical server
  • Data Disk Can be optionally added but it will also be from a differnt physical server
  • Temp Disk of a certain size would be created from the same physical server as VM.
• Impact of This:
  • When you stop the vm (the resources of the vm) from the physical server gets deallocated so VM & temp disk will be deallocated & when you start the vm again, vm will be allocated on a certain physical server with a new temp disk. Where as OS Disk & Data Disk will not have any impact.
• Number of Data disks and size of temp disk is dependent on VM Size
• Activity:
  • Create a Linux VM with Size Standard_B1s in a resource group (new => exploring)
  • Navigate to the resource groups and check for the disks created
  • SSH into the linux machine and execute the following commands and take screen shots

  sudo lsblk
  sudo df -h
  

  
  • Lets add one data disk
  • Now execute sudo lsblk
  • Lets try to mount this disk on folder tools

  sudo mkfs -t ext4 /dev/sdc
  sudo mkdir /tools
  sudo mount /dev/sdc /tools
  sudo df -h
  

  
  • Now execute the following commands

  sudo blkid
  sudo nano /etc/fstab
  

  
  • Now lets add some content to os disk, data disk and temp disk

  # os disk
  sudo mkdir /dummy
  sudo touch /dummy/{1..100}.txt
  # data disk
  sudo mkdir /tools/dummy
  sudo touch /tools/dummy/{1..100}.txt
  # temp disk
  sudo mkdir /mnt/dummy
  sudo touch /mnt/dummy/{1..100}.txt
  

  
  • Stop the VM
  • Wait for the vm to be stopped and start again and try to verify the contents
    • Data in temp disk will be lost
    • Data in os & data disk will be persistent