Microsoft: Here's what caused our cloud outage this week

Microsoft officials are starting to share some details with customers and partners about what led to several cloud-service outages this week.

On August 17, many North American users of Microsoft Office 365 and SkyDrive were unable to access their email and calendars due to a three-plus-hour outage.

Some Dynamics CRM Online users also experienced service problems that day, but Microsoft execs are not saying the two sets of issues were due to the same root cause. The Dynamics CRM team has declined to provide information on what led to Wednesday's outage or on how many users were affected. (Microsoft officials have said that Microsoft is planning to add CRM Online to the company’s hosted Office 365 suite — which currently includes Microsoft-hosted Exchange, SharePoint and Lync — before year-end.)

Update: The Dynamics team sent this update via a company spokesperson:

“The root cause of the Microsoft Dynamics CRM Online service has been identified as a site configuration issue. A configuration change was made in all data centers that should prevent this from happening again. This was not a complete outage and separate from any other service issue experienced by customers. ”

While not sharing exact details, Microsoft officials are attributing the Office 365 problems to "a networking interruption" in one of its North American datacenters. One of my contacts said he believed faulty Cisco networking gear was the culprit -- something Microsoft a Microsoft spokesperson didn't confirm (or deny) when I asked.

Microsoft sent out notes to Office 365 customers using the affected Microsoft-hosted services on August 18 informing them of their initial findings and plans to credit affected users with 25 percent of their monthly invoices. Here is a copy of the note Microsoft e-mailed to customers:

Dear Customer:

The Office 365 team strives to provide exceptional service to all of our customers. On August 17, customers served from one of our North America data center lost access to email services included in the Office 365 suite. We apologize for the inconvenience this may have caused you and your employees.

We are committed to communicating with our customers in an open and honest manner about service issues and the steps we’re taking to prevent recurrences.

•What happened?

º Preliminary investigation indicates that a networking interruption in one of our North America data centers caused Office 365 Exchange Online to be inaccessible by some customers. º This incident lasted from approximately 11:30 AM PDT to 2:40 PM PDT, during which time customers were not able to access the Outlook Web App or send and receive email through Exchange Online. º The Service Health Dashboard was updated regularly during the event to notify customers of the problem, though there was a brief period of intermittent access issues to that dashboard.

• What actions have been taken to prevent a recurrence?

º The data center’s networking facilities have been remediated and we are investigating the root cause. º We continue to monitor the overall network very closely to maintain high levels of service to customers.

We understand that any disruption in service may result in a disruption to your business. As a gesture of our commitment to ensuring the highest quality service experience Microsoft is proactively providing your organization a credit equal to 25% of your monthly invoice. The credit will appear on a future invoice, and you do not need to contact Microsoft to receive this credit. Please note, processing of the credit may take as long as 90 days.

If you have additional questions, please do not hesitate to contact us at the Office 365 community site.

Thank you for choosing Office 365 to host your business productivity applications. We appreciate your business.

Sincerely,

The Office 365 Team

Microsoft launched Office 365 at the end of June and have on-boarded number of customers and partners since then. Microsoft also has moved some of its existing BPOS (Business Productivity Online Suite) users onto Office 365, but has advised the majority of BPOS users interested in Office 365 to wait until September before the migration process will begin in earnest.