Understanding Microsoft’s Explanation of Azure VM Specs

This post is a part of a series:

I have a great laugh when I am in front of a room and explaining Microsoft’s Azure VM specs to people. Take a look at this screenshot from the pricing site:

imageLet me ask you a few questions about the Basic A1 VM:

  1. How much disk space does that VM have?
  2. How many data disks can that VM be allocated?
  3. What is the max IOPS of each data disk?
  4. What are the maximum number of virtual NICs can that VM have?

Let me give you a clue:

  1. The answer is not 40 GB
  2. You don’t have enough information
  3. You don’t have enough information
  4. You don’t have enough information

We have answered 1/4 questions from the pricing site.

Let’s go dig for information on the Sizes For Virtual Machines page. Here we get a different set of information:

imageLet’s try answer those questions about the Basic A1 again:

  1. The answer is not 1063 (1023 + 40) GB
  2. A maximum of 2 data disks is correct
  3. Each data disk can have up to 300 IOPS. With 2 data disks, we can have an aggregate of 600 IOPS using Storage Spaces, etc, in the guest OS
  4. You still don’t have enough information.

OK, we now can answer 2/4 questions correctly! Let’s go to a reliable tool: Google. I found Create A VM With Multiple NICs. There I have found the below:

image

Now I can update my answers:

  1. The answer is not 1063 (1023 + 40) GB
  2. A maximum of 2 data disks is correct
  3. Each data disk can have up to 300 IOPS. With 2 data disks, we can have an aggregate of 600 IOPS using Storage Spaces, etc, in the guest OS
  4. A Basic A1 VM can have 1 virtual NIC

OK, would someone please tell me how much storage space will be consumed if I deploy a Basic A1 VM with Windows Server?!?!?!?!

The answer is that the C: drive of any Windows Server VM that is deployed from the Marketplace is 127 GB. The D: drive (a temporary drive that you should not store persistent data on) is indicated in the pricing. So, the Basic A1 VM will deploy a 127 GB C: drive and a 40 GB D: drive.

    1. How much disk space does that VM have? 167 GB.
    2. How many data disks can that VM be allocated? 1 maximum of 2.
    3. What is the max IOPS of each data disk? 300 IOPS.
    4. What are the maximum number of virtual NICs can that VM have? It can have 1 vNIC.

[EDIT]

I found another nugget of information today while pricing up DS-Series and GS-Series virtual machines. Microsoft says that DS-Series cost the same as D-Series. That’s no longer the case; D-Series was reduced in price on Oct 1st 2015, and DV2-Series was introduced as an upgrade. Now DS-Series costs the same as Dv2-Series at this time. GS-Series is still (at this time) the same price as G-Series.

If only there was a website with that information!

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