Google Apps vs. Office 365 – A comparison of Gmail and Exchange system availability

Google Apps vs. Office 365 – A comparison of Gmail and Exchange system availability

With Google’s recent announcement that 2012 Gmail availability was 99.983%, fundamental differences between Gmail and Office 365’s Exchange Online service are becoming increasingly obvious. In particular, Google’s uptime announcement highlights the differences in system availability, transparency and architecture between the two messaging services.

System Availability

In looking at Microsoft Office 365 Incident reports over a 151 day period (9/23/2012 to 2/2/2013), we tabulated 18 unique Exchange incidents. These incidents, and scheduled downtime windows, represent a total of 4,503 minutes of downtime, or 3 days, 3 hours and 3 minutes. By our calculations, that comes to a 97.929% availability during this period; not quite the 99.9% Microsoft promises its customers. By comparison, Gmail was available 99.983% of time. Over a similar 151 day period, this amounts to an average of 44 minutes of downtime.

So what does this mean to customers looking at the two systems? It means that for every 1 minute of Gmail downtime, Exchange Online is down for 103 minutes! Now imagine the financial impact an Exchange outage can have on an your organization…


Google’s uptime announcement also reveals another important disparity between the two services: transparency. Google publishes performance information publicly in the Google Apps Status Dashboard, a web page that anyone can access whether they are a paying Google Apps customer or not. The dashboard displays real-time performance information for all Google Apps services. Google updates the dashboard with performance information as it happens to ensure a high level of transparency.

Microsoft has a similar dashboard — but unlike Google’s public Apps Status Dashboard, Microsoft’s dashboard is protected, visible only to paying Microsoft Office 365 customers. This prevents prospective Microsoft customers from fully researching the service and having a complete picture before making a purchase decision. Furthermore, it prevents anyone who isn’t a domain administrator from accessing the dashboard. So without an administrator’s help, key decision makers at a company using O365 — like the CEO — would not be able to see if email is down for the entire company. Microsoft does not publish what percentage of its users are affected by outages, and only relates what Regions were affected when they can definitively determine this information.

Global Business Needs a Truly Global Architecture

A final point that Google’s announcement emphasizes is the difference in the architecture on which each solution is based. Google offers a true multi-tenant, scalable, grid architecture that was purpose-built for the cloud. This cloud architecture means that Google does not require any planned downtime and does not provide for any downtime in their SLA. On the other hand, Exchange Online is essentially hosted Exchange in a Microsoft datacenter. Microsoft’s “cloud” is built on the same code base that customers can run in their own datacenter and requires regularly scheduled downtime for updates, patches and hotfixes (Does “Patch Tuesday” ring a bell?). This hosted architecture is retrofit for the cloud and it requires organizations to choose one primary data center for their system, typically based off of the organization’s corporate “ship to” address. Having to make this decision can cause performance to suffer in offices that are particularly far from the designated data center.

In an ever-growing global economy, organizations need to make informed decisions about which service providers can best meet their needs. In order for CEO’s to make such decisions, they must first understand which provider is best positioned to handle rapid growth and to make a viable uptime commitment. With this in mind, comparing Microsoft and Google side-by-side begs the question: Which service provider is best positioned to meet these needs — one that was born in the older, client-server architecture who is just now retro-fitting to the cloud and obscuring uptime statistics or one that was born in the cloud on a truly global infrastructure and is completely transparent about its availability?


Derik VanVleet
Derik VanVleet 69 Posts

Derik is the Director of Cloud Strategy at Cloud Sherpas, and has a deep technical knowledge of Active Directory, Windows, Exchange, Business Development, Identity Management, Partner Development, Google Apps and Google Enterprise.