Posey's Tips & Tricks

Office 365: The Cloud of Choice for Exchange Server?

For those who can't decide whether to host their Exchange Server in Azure or Office 365, here are some considerations to factor in.

Last week I received an e-mail from a reader who wanted to know if it was possible to run Exchange Server in Azure. He wanted to run Exchange Server in the cloud, but wanted to avoid using Office 365 if at all possible. When I asked him why he didn't want to use Office 365, he indicated that he already had an Azure subscription and didn't want to deal with the hassles of setting up and paying for yet another cloud subscription. He was also hoping to avoid delving into the complexities of Office 365 directory synchronization.

For years Microsoft expressly prohibited its customers from running Exchange Server on Azure. Earlier this year however, Microsoft began officially supporting the practice -- at least for Exchange Server 2013. Of course this raises the question of whether you should be running Exchange Server in Office 365 or in Azure.

Let me just say up front that my personal preference is to run Exchange locally, but this is just a preference. My only real rationale behind this preference is the fact that I am a control freak and like having my Exchange Servers close at hand. In spite of this preference, I use Office 365 for my production Exchange mailboxes. It isn't that I wouldn't like to run Exchange in house. It's just that several years back I had an Exchange Server outage while I was on the other side of the world and couldn't do anything about it. That outage cost me a lot of money and more or less forced me to move my Exchange deployment to the cloud.

So let's go back to the original question. Is it better to run Exchange in Office 365 or in Azure? In my opinion, there is a case to be made for each. For most organizations however, I think that Office 365 is the better solution.

The most obvious reason for this is that Office 365 is hassle free. Microsoft handles the installation, most of the configuration and the ongoing maintenance for you. You can be sure that Office 365 is configured correctly by Microsoft and that it complies with Microsoft's established best practices.

Another reason why Office 365 might be the better choice is because it offers flat rate pricing.  Office 365 subscriptions are licensed on a per user basis. If you know how many users there are in your organization, then there shouldn't be any surprises when the bill comes.

Conversely, Azure pricing is based on resource consumption. Your bill can fluctuate based on how hard your Exchange Servers are working. Furthermore, if you decide to deploy additional Exchange Server virtual machines for the sake of load balancing or fault tolerance, then your cost will go up because you are consuming more resources. On the other hand, Microsoft handles load balancing and fault tolerance behind the scenes in Office 365, so you never have to worry about the cost or the complexities of high availability.

OK, so I have talked all about the virtues of running Exchange as a part of an Office 365 subscription, but what about Azure? Under what circumstances would it be better to run Office 365 in an Azure environment?

There are two situations in which I think it is better to run Exchange in Azure than in Office 365. First, you should consider running Exchange in Azure if you want to do your own thing. Office 365 is nice in that Exchange Online is preconfigured according to Microsoft's established best practices. But let's face it, sometimes in the real world there are circumstances that require running a configuration or a topology that would not necessarily be recommended under normal circumstances. Running Exchange Server in Azure gives you exactly the same degree of control that you would have if you were to run Exchange locally in your own datacenter, which means that you are free to do your own thing.

The other situation that warrants running Exchange Server in Azure is using external software with Exchange. If you developed Exchange-specific PowerShell scripts when Exchange was running in your own datacenter and want to continue to use those scripts after moving Exchange to the cloud, then you may need to run Exchange on Azure (depending of course on what the scripts actually do). Similarly, there are a lot of third-party applications that do not work with Exchange Online in Office 365. If you have a backup solution or a monitoring solution that isn't Office 365 compatible, then you may want to use Azure.

As you can see, Office 365 and Azure each have their place. Ultimately, you will want to choose the solution that is the best fit for your organization's own unique needs.

About the Author

Brien Posey is a 16-time Microsoft MVP with decades of IT experience. As a freelance writer, Posey has written thousands of articles and contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and health care facilities. He has also served as a network administrator for some of the country's largest insurance companies and for the Department of Defense at Fort Knox. In addition to his continued work in IT, Posey has spent the last several years actively training as a commercial scientist-astronaut candidate in preparation to fly on a mission to study polar mesospheric clouds from space. You can follow his spaceflight training on his Web site.


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