Data Backup Digest

Microsoft Windows Azure, released in 2010, is currently one of the most widely used cloud computing platforms in the world. Featuring extensive support for programming languages, frameworks, and software, Azure has already cemented itself amongst the most comprehensive cloud computing systems available. However, this doesn't mean that the service has been fully perfect. In fact, the new read-access georedundant storage option, which is currently undergoing live testing in a limited trial, proves there is still room for improvement in cloud technology.

What is Georedundant Storage?

Some cloud users may already be familiar with the term of geographically redundant storage, also known as GRS, which has become the default setting for new Windows Azure Storage accounts. While this has been used since the beginning to replicate stored data between two geographically separated regions, thereby ensuring data integrity and continuity, their new read-access georedundant storage, known as RA-GRS, basically provides a second option for users who are having trouble accessing their stored data. In the event that their primary storage account is unavailable or unreachable, the secondary account can be used to fill the void.

Physical Location

Windows Azure Storage users usually have the option of selecting the primary storage site for their own cloud-based storage. With RA-GRS, Microsoft has full control over the secondary site. There are some common site correlations, however, as Microsoft pointed out in their original blog post. Users who opt for a primary site in the northern U.S. will typically be assigned a secondary site located within the southern U.S., while those who choose a primary site in the east will usually receive a secondary site in the west. This same process applies not only within the United States, but to locations through Europe, Asia and China, as well.

One important point to note, however, is the fact that there is a slight delay between the primary and secondary sites during the data replication process. If the data has not yet been replicated to the secondary site available with RA-GRS, and if it is not accessible or recoverable from the primary site, then it may be lost for good.

How it Compares

The newly introduced read-access georedundant storage, although slightly more costly than Azure's standard services, offers a higher read availability of 99.99% compared to that of 99.9% with their original GRS. While this may not seem like much, an enterprise that depends on cloud storage on a day-to-day basis may find that read-access georedundant storage is the failover solution they've been looking for.

Signing Up for RA-GRS

As mentioned earlier, the read-access georedundant storage feature is still in its testing and preview phase. Current users of Windows Azure Storage can sign up for RA-GRS through the Preview Services webpage of Azure. Once confirmed, you can activate RA-GRS through the Windows Azure Management Portal. Note that users of RA-GRS will be charged for a minimum of 30 service days, which begins the moment your RA-GRS service is enabled. Like Azure's other services, RA-GRS is available in pay-as-you go plans as well as increments of six or 12 months.