If you felt like Gmail was behaving strangely yesterday, you’re not alone. What first appeared to be a minor service disruption escalated into an issue that affected nearly 50% of all Gmail and Google Apps users.

Users began reporting issues with the delivery of messages being delayed, as well as attachments failing to download.

Fortunately this issue appears to have been resolved completely, with Google commenting on the issues via the Google Apps Status Dashboard:

The problem with Gmail should be resolved. We apologize for the inconvenience and thank you for your patience and continued support. Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better.

 

As of 1600 Pacific Time, Gmail message delivery and attachment download is functioning normally for all users. We apologize for the duration of today’s event; we’re aware that prompt email delivery is an important part of the Gmail experience, and today’s experience fell far short of our standards.

While service disruptions such as this can be frustrating, it’s important to note that products such as Gmail (and a majority of the Google Apps suite) are covered under Google’s Service Level Agreement (SLA). This means that Google ensures the products will be operational 99.9% of the time, or customers will be eligible for credits.

On the plus side, at least you finally have a legitimate excuse for all the emails you didn’t answer yesterday!

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Update – Google released a little bit more information about the cause of the interruptions through the Official Gmail Blog:

The message delivery delays were triggered by a dual network failure. This is a very rare event in which two separate, redundant network paths both stop working at the same time. The two network failures were unrelated, but in combination they reduced Gmail’s capacity to deliver messages to users, and beginning at 5:54 a.m. PST messages started piling up.

If you’re curious if this is likely to occur again, Google addressed that as well:

What’s next? Our top priority is ensuring that Gmail users get the experience they expect: fast, highly-available email, anytime they want it. We’re taking steps to ensure that there is sufficient network capacity, including backup capacity for Gmail, even in the event of a rare dual network failure. We also plan to make changes to make Gmail message delivery more resilient to a network capacity shortfall in the unlikely event that one occurs in the future.