Windows Azure FAQ #145: What Size VM Should I Go With?

A fresh new entry was recently placed into the treasure trove of “buried” Windows Azure content.  This one is certainly a frequently asked question I get when talking to folks about hosting their applications in Windows Azure’s compute service.  Check out:

Real World: Considerations When Choosing A Web Role Instance Site: How Small Should I Go?

treasuretroveThis article was published on MSDN by Joel Forman and Stephen Roger.  Joel and Stephen are both consultants at Slalom Consulting.  This article was shared with me by Bill Zack.  (Some of you may recall Bill Zack from his days at Microsoft evangelizing Windows Azure.  Bill is still kicking it over at Slalom NYC these days along with other former ‘softies like Asli Bilgin.)

Windows Azure (and cloud computing in general) offers developers the ability to build web applications that can easily scale “out” with multiple virtual machines.  It also offers the ability to easily scale “up” with larger VMs that have extra resources dedicated to them (memory, bandwidth, etc). 

If you examine the compute pricing table for Windows Azure, you will see that VMs come priced primarily by the number of CPUs. Sizes range from Extra Small, through Small, Medium, and Large, to Extra Large.  You can run four “Small” VMs (single CPU) for the same price ($0.48/hour) as two “Mediums” (2 CPUs), giving you 4 CPUs in either configuration.  But which is better?  And why?

These are the types of questions Joel & Stephen attempt to answer in the article.  They walk you through a test web app and the performance tests they ran to come up with their recommendations.

Here’s some info on the authors:

About Stephen Roger

Stephen Roger is the Managing Director for Slalom Consulting’s National Microsoft Practice. The National Microsoft Practice is focused on creating solutions for clients that leverage the latest platform technologies including the Windows Azure Platform.

Slalom Consulting has been working with the Windows Azure Platform for over 3 years with well over 50+ successful engagements. Stephen has been directly involved in many of these engagements from a Program and Project Management perspective.

About Joel Forman

Joel Forman, a Cloud Architect with Slalom Consulting, is helping drive Slalom’s Windows Azure Platform Practice. He has been working with the Windows Azure Platform since 2008 (prior to its public announcement) and now has over 3 years of experience building cloud solutions.

Joel has been the technical lead on the delivery of numerous production Windows Azure applications. His experiences span platform capabilities and include authentication and authorization with the Access Control Service, improving performance with the Content Delivery Network, and hybrid cloud/on-premise architectures. In addition to technical delivery, Joel also conducts assessments and training workshops with clients evaluating Windows Azure.

Joel frequently blogs and tweets on Windows Azure Platform topics. You can follow him on Twitter at and through his blog posts at