Amazon might be the cloud provider to beat, but Microsoft claims that more than half of the Fortune 500 are among the quarter of a million customers now using Azure.
The company announced the milestone late last week, which came just over three years after its cloud platform became commercially available.
In the past year, Microsoft has doubled its Azure customer base to 250,000 and claims to be averaging around 1,000 new customers per day.
Microsoft is boosting capacity at an even faster rate than customer growth, claiming it has doubled its Azure compute and storage capacity every six to nine months along with expansions in Japan, Australia and its 21Vianet-operated Chinese Azure cloud.
Like Amazon, Microsoft does not reveal stored data in byte terms, but reflects "increase in usage" by showing off the number of objects stored in Azure.
"With over four trillion objects in Windows Azure and an average of 270,000 requests per second, customer requirements grow and are met daily. In peak periods, demand can grow to a staggering 880,000 requests per second," Steven Martin, general manager for Windows Azure, wrote on the Azure blog.
Oddly, the figures are identical to those given by Microsoft's general manager for Azure Storage Brad Calder last July, suggesting perhaps that Microsoft has not updated its figures. Microsoft had just one trillion objects in Azure in 2011.
Meanwhile Amazon in April revealed it had two trillion objects stored in Amazon S3, and said it was regularly peaking at more than 1.1 million requests per second. Last year it announced its first trillion objects, which took it six years to reach.
Last week Microsoft also launched another Azure feature called Active Authentication, which is built on technology from PhoneFactor, a multifactor mobile authentication firm Redmond .
The service allows customers to enable multifactor authentication for Windows Azure Active Directory identities to provide secure access to Microsoft cloud products such as Office 365, Azure, Windows Intune, Dynamics CRM Online as well as other apps integrated with the Active Directory.