Microsoft Windows Azure Drive Beta Released

Microsoft released a beta version of Windows Azure Drive, which allows users to port their applications from a localized Windows environment to the Windows Azure environment within a cloud, on Feb. 2.

"Customers have told us they want to take their already running Windows applications and run them in the cloud using the standard Windows NTFS APIs, and make sure that the data is durable," Brad Calder, a member of the Windows Azure Storage team, wrote in a Feb. 2 posting on the Windows Azure Team Blog. "With Windows Azure Drive, your Windows Azure applications running in the cloud can use existing NTFS APIs to access a durable drive. This can significantly ease the migration of existing Windows applications to the cloud."

Calder continued: "The Windows Azure application can read from or write to a drive letter…that represents a durable NTFS volume for storing and accessing data. The durable drive is implemented as a Windows Azure Page Blob containing an NTFS-formatted Virtual Hard Drive (VHD)."

During the beta period, customers will only be billed for storage space used by the Page Blob, along with any read-and-write transactions to the Blob.

"The Page Blob can be mounted as a drive only within the Windows Azure cloud, where all non-buffered/flushed NTFS writes can be made durable to the drive," Calder added. "If the application using the drive crashes, the data remains persistent via the Page Blob, and can be remounted when the application instance is restarted or remounted elsewhere for a different application instance to use."

The Windows Azure SDK will offer a variety of Windows Azure Drive APIs, including Create Drive, Initialize Cache, Mount Drive, Get Mounted Drives, Unmount Drive, Snapshot Drive, and Copy Drive. A full explanation of those APIs and their capabilities can be found here, along with some high-level points about the application’s capabilities.

Microsoft announced that the Windows Azure platform, Microsoft’s competitor in a cloud-computing space increasingly crowded by the likes of Amazon and Google, became generally available in 21 countries starting on Feb. 1. In the process, Windows Azure and SQL Azure stopped being free, starting at 12:00 am GMT on Feb. 2 in order to give all those countries the chance at a full January of free service.

The Azure platform consists of three components: Windows Azure, the operating system as a service; SQL Azure, a cloud-relational database; and Windows Azure Platform AppFabric, which provide secure connectivity and federated access control for applications.

Customers who choose to not upgrade their Windows Azure Community Technology Preview (CTP) accounts will have their service disables and their Windows Azure storage rendered read-only, while SQL Azure CTP customers will be unable to create new databases. SQL Azure CTP accounts and Windows Azure Storage CTP accounts will be deleted on March 1 and April 1, respectively, for those who do not choose to upgrade.

Azure payment options include a pay-as-you-go model, a subscription format and volume licensing. Microsoft is rolling out the platform at a time when the cloud-computing market has been estimated at around $150 billion, and competitors such as Google and Amazon have produced their own offerings for businesses and developers. Other Microsoft cloud-based initiatives include Windows Server 2008 R2 Hyper-V virtual machine support on Azure, Microsoft Pinpoint Marketplace for marketing and selling applications through the cloud, and stripped-down online versions of its Office 2010 applications.