Using WebDAV to Simplify Backup and Recovery in the Cloud

Cloud storage or local disk drive? That's the question.

The trouble with cloud storage in general, and backup and recovery in particular, is that most people find the whole process cumbersome—and the recovery process unreliable. As a result, many don’t bother with backup, even in an age where cloud computing has theoretically made storage ubiquitous.

One could argue the root of the problem lies in backup and recovery systems designed for IT pros working with tape-drive technologies.

From the average IT person’s perspective, cloud storage comes down to swapping out the backup device from a tape or disk drive in a local data center, and transferring its contents to a remote server in the cloud. Of course, that involves transferring files across wide area networks, which can be expensive, and the end result isn’t necessarily any more reliable.

Indeed, end users wrestling with backup and recovery often complain the files they’re recovering are corrupted. In an ideal world, the integrity of said backup files would have been tested beforehand. However, most people are so numbed by the backup process, they don’t really have the time or emotional wherewithal to test. Instead, they hope and pray things will work—or better yet, that nobody ever needs that file.

Against that backdrop, it’s interesting to note the emergence of a relatively old Web technology to solve a problem in the cloud. Web Distributed Authoring and Versioning (WebDAV) is an extension of the HTTP that was originally created to facilitate collaboration between users in editing and managing documents and files stored on the Web. Intended to solve a document collaboration problem, a few cloud storage vendors have been using WebDAV to solve some of the thornier problems associated with backup and recovery in the cloud.

Case in point is Zetta.net, a cloud storage service that uses WebDAV to allow customers to backup and retrieve files without requiring the use of any local appliance. Recently, the company unfurled version 3.0 of Zetta DataProtect, which adds expanded support for SQL, Windows System State, Microsoft Exchange, unstructured data files and VMware. In addition, the new release features support for Macintosh systems alongside Windows and Linux clients.

What makes WebDAV in the context of Zetta.net efficient is that WebDAV is not only bundled into every major operating system, once the initial file transfer is completed the only thing that has to transferred again are the actual changes to the data in the file, as opposed to backing up the entire file all over again. That capability, along with the use of local metadata cache, de-duplication and advanced network data compression technologies makes it possible for Zetta.net to charge a flat fee that starts at $949 a month for up to 2TB of storage.

Customers such as Larry Steinke, technology director for Saint Francis High School in Mountain View, Calif., confirm Zetta.net’s method makes it easy to find specific files when they need them. “What I like most is getting the files back,” Steinke said. “I don’t have a lot of extra time or a big IT staff. All we gave to do is browse a directory tree to get back the file we want.”

He also noted that each backup comes with a report, eliminating guesswork over whether a backup was completed successfully.

Meanwhile, companies such as BackupAssist also rely on older open-source technologies such as Rsync to back up files to any cloud service platform that supports that protocol, including Amazon.com.

But as widely used as WebDAV and Rsync have become, some argue that no open-source technology will scale efficiently in the age of the cloud. As a result, cloud storage providers such as Axcient have developed proprietary protocols for moving files to and from the cloud in a more efficient manner. “We originally got started using webDAV,” said Axcient CEO Justin Moore, “but we quickly discovered that while it saved us some money on set up costs because it was open source, it just wouldn’t scale.”

Because Axcient’s approach to backup and recovery can scale, Moore believes that Axcient can compete on price with any cloud service provider, even though the company incurs the expense of hiring engineers to develop and maintain the overall environment.

Whatever their approach, most cloud storage providers are trying to eliminate the need to use traditional backup and recovery software. Ultimately, backup and recovery in the age of the “consumerization of IT” needs to be as simple and reliable as possible. Anything short of that gives backup and recovery a bad rep, especially when people put data at risk because they consider backing up files too much trouble.

 

Sidenote: Open Source Backup Recovery Technologies

Web Distributed Authoring and Versioning (WebDAV) is an extension of the Hypertext Transfer Protocol (HTTP) that facilitates collaboration between users in editing and managing documents and files stored on World Wide Web servers.

The WebDAV protocol makes the Web a readable and writable medium. It provides a framework for users to create, change and move documents on a server. The most important features of the WebDAV protocol include maintenance of properties, such as the creation, removal, and querying of file information.

rsync is a software application and network protocol for Unix-like and Windows systems that synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync, not found in most similar programs/protocols, is that the mirroring takes place with only one transmission in each direction. rsync can copy or display directory contents and copy files, optionally using compression and recursion.

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