Google, hoping to persuade businesses to shift away from Microsoft's email technologies, this morning announced changes in the service level agreement -- better known in the industry as an SLA -- that governs the reliability of its Gmail service.

The effect is to remove a pair of exceptions in the Gmail SLA that previously kept certain types of outages from counting toward the downtime allowed by the agreement. Here's the key excerpt from the post on the Google Enterprise Blog:

Unlike most providers, we don't plan for our users to be down, even when we're upgrading our services or maintaining our systems. For that reason, we're removing the SLA clause that allows for scheduled downtime. Going forward, all downtime will be counted and applied towards the customer's SLA. We are the first major cloud provider to eliminate maintenance windows from their service level agreement.

We're also amending our SLA so that any intermittent downtime is counted. Previously, a period of less than ten minutes was not included. We believe any instance that causes our users to experience downtime should be avoided -- period.

Google and Microsoft are battling it out for key government and business contracts, particularly as Microsoft expands to offer its own cloud-based email and collaboration services.

Previously: How Ballmer courted U.S. deal, and how Google won injunction