none
Storage calculation and pricing

    Question

  • Hello all,

    I've got a quick question about how Azure storage is calculated and how that effects the pricing.

    I'm planning to migrate around 100 VM's to Azure IaaS, on average a server will contain an OS disk and at least 1 or 2 data disks. I'll be using a regular, locally redundant storage account (no geo replication, no premium storage).

    Seeing the complexity of resizing disks of Azure VM's (deallocate VM, remove VM configuration, download disk, extend disk with xx GB's, upload disk, create VM configuration, start VM) wer're considering to increase the disks of our on-premise VM's to the max allowed capacity for an Azure VM (OS disk 127GB, datadisks 1024GB).

    However, doing this would leave a lot of free space on the disks. If I extend a datadisk to 1024 GB and in practice I only put 24GB of actual data on the disk (leaving me with 1000GB empty space), would I be billed for 1024 GB (actual disk size) or 24 GB (actual amount of data on the disk).

    I found the following statement in the Azure Storage FAQ:

    "If I attach an empty 100GB disk to my virtual machine, will I be charged for the entire 100 GB or just the storage space I use?"

    "If the empty 100GB disk is backed by a Premium Storage Account then you will be charged for a P0 (128GB) disk. If any other type of Storage Account is used then you’ll only be billed for the storage space used to store the data that is written to the disk regardless of the allocated disk size."

    After reading I'm tempted to think I would only be charged for the 24 GB but some (more clear) information would be appreciated.

    Cheers


    Friday, August 21, 2015 12:39 PM

Answers

  • Yes, that is correct for Standard storage disks. You only get billed for the actual data used. In this example, 24GB. Having a disk size of 1024 GB has no effect on billing.

    Separately, I want to clarify the concern about resizing the disk. Azure recently added a capability to easily increase disk sizes. You can expand the disk using “Update-AzureDisk” PowerShell commandlet with “-ResizedSizeInGB” property. Before performing this action, the disk needs to be detached from the VM (or you can stop the VM instead). After updating, you can reattach the disk (or start the VM) and it will have the larger disk size you specified.

    Friday, August 21, 2015 9:48 PM

All replies

  • In Azure you are billed only for actual data.

    So if you have 100GB VHD with 20GB used and 80GB empty, you will be billed for 20GB.


    Mustafa Toroman

    • Proposed as answer by JayChase Saturday, August 22, 2015 12:01 AM
    Friday, August 21, 2015 1:10 PM
  • Yes, that is correct for Standard storage disks. You only get billed for the actual data used. In this example, 24GB. Having a disk size of 1024 GB has no effect on billing.

    Separately, I want to clarify the concern about resizing the disk. Azure recently added a capability to easily increase disk sizes. You can expand the disk using “Update-AzureDisk” PowerShell commandlet with “-ResizedSizeInGB” property. Before performing this action, the disk needs to be detached from the VM (or you can stop the VM instead). After updating, you can reattach the disk (or start the VM) and it will have the larger disk size you specified.

    Friday, August 21, 2015 9:48 PM