Read an interesting article this morning in The Register: Microsoft hit by cloudy downtime in US. This is one of the key reasons why large enterprises’ are being very cautious about moving their email infrastructure to the cloud. Yes, there are positive economic reasons for doing so, but there are also risks. A two-hour email outage can cost some business a lot of money, not to mention poor customer service which can lead to lost customers. I realize an on-premises infrastructure can also fail, but your own IT organization has more control over it and can put the necessary redundancy in place to mitigate long outages.
The promises of cloud computing can potentially be realized by migrating different layers of the messaging infrastructure to the cloud, and Sendmail has worked with many Fortune 1000 companies that have done so successfully. However, virtually all of those enterprises have an on-premises email backbone layer that glues all of the layers together. Check out this paper to learn more, and feel free to let me know what you think.