For more information about disks, see About Virtual Machine Disks in Azure.
##How to: Attach an empty disk Attaching an empty disk is the simpler way to add a data disk. Run the following command to attach a new empty disk:
vm disk attach-new <vm-name> <size-in-gb> [blob-url]
Replace vm-name with the name of your virtual machine, and size-in-gb with the size of your new disk. You can optionally use a blob URL as the last argument to explicitly specify the target blob to create. If you do not specify a blob URL, a blob object will be automatically generated.
Run the following command to verify that your disk has been created:
vm disk list <vm-name>
Here is a sample walkthrough of the above commands including terminal output:
~$ azure vm disk attach-new pinkylinux 20 http://pinkylinux.blob.core.windows.net/vhds/pinkydisk1.vhd
info: Executing command vm disk attach-new
+ Getting virtual machines
+ Adding Data-Disk
info: vm disk attach-new command OK
~$ azure vm disk list pinkylinux
info: Executing command vm disk list
+ Fetching disk images
+ Getting virtual machines
+ Getting VM disks
data: Lun Size(GB) Blob-Name OS
data: --- -------- -------------------------------------- -----
data: 30 pinkylinux-pinkylinux-2015-02-05.vhd Linux
data: 0 5 pinkydisk1.vhd
data: 1 20 pinkylinux-f8ef0006ab182209.vhd
info: vm disk list command OK