Forrester Defines Three Cloud Storage Use Cases

While a lot of hype has been generated about cloud computing, particularly storage in the cloud, Forrester Research senior analyst Andrew Reichman contends that are really only three situations in which cloud storage is a viable alternative to managing storage on-premises: when supporting cloud applications, as secondary back-up and for file storage of infrequently used files.

The first in his list, storage of data for applications that are also delivered in the cloud, is commonly known as Software as a Service (SaaS). Typically, businesses delve into cloud computing one application at a time and sign up for SaaS services such as e-mail in the cloud from Google or customer relationship management software from Salesforce.com. "If an app is moving from on-premises to the cloud, that changes how much storage on-premises you're going to need," said Reichman, who also advised that the SaaS vendor needs to accurately determine how much storage the customer's application is going to need. It's also not uncommon for a business to have different cloud vendors for different applications because each may have particular expertise in one app area or another, he said.

Second, cloud storage would be appropriate for secondary backup of data. Storage needs to be in the same location as the application servers so data is saved to storage quickly, but backup storage could and should be off-site for disaster recovery purposes, and the cloud could be a suitable solution, Reichman said.

However, the cloud provider needs to have enough bandwidth to return data quickly to the customer's data center when needed. As he explains it, data is saved to storage from the application server a little bit at a time, but when a failure occurs and the backup storage is called to action, it needs to send all the data stored over time at once. "When you're restoring, you're potentially talking about a huge amount of data where all the data that's on that server has to go back across the wire. That is a potential bandwidth problem," Reichman said.

Third, cloud storage is ideal for file storage. About 80 percent of files stored by a given organization are accessed infrequently, sometimes not at all, so they could be stored in a cloud if an organization is willing to tolerate some degree of slower access to them. As it is, remote offices would experience a delay in accessing documents on a file server at the home office anyway, so accessing those files in the cloud would take about the same amount of time.There are a couple of scenarios in which cloud storage would not be the answer. The cloud would not work as well for data warehousing in which one database is accessed by several different applications. He also advises against running an application in the customer's data center but the storage in the cloud because of concerns about latency.

It's not that cloud vendors are pushing cloud services that are inappropriate, it's that cloud marketing is so pervasive. "It's kind of maddening how much cloud hype there is," said Reichman, who's heard pitches that the traditional data center is disappearing, that everything will be available in the cloud and that customers won't need to buy storage technology themselves anymore. "Anything's possible in 10 [or] 15 years, but for what we've got going now, those are the types of claims that just don't seem that likely," he said.

It's critical for customers to craft well-defined service level agreements (SLAs) in contract negotiations with cloud vendors to guarantee what level of availability, performance and security the vendor will provide, Reichman added. It may be one thing for the vendor to deliver high performance and availability to one of its first customers and quite another matter when it adds 100 more over time.

Lastly, Reichman advises companies to ask for discounts from cloud vendors for being early adopters. The vendor may easily agree to a discount if that means that company can be a reference customer for it to market to other prospects.