INDUSTRY INSIDER

Continuous Data Protection a Better Backup Option

Let’s be honest: Backup is an unloved necessity. It costs money and takes time. Restores are time-consuming and frustrating. But the fact is, you cannot live without them. Data must be backed up; it must be protected. Continuous Data Protection (CDP) offers a way to backup and restore data faster — with better reliability — all while actually reducing costs.

The traditional, time-honored approach has been backup to tape. Tape was a less costly medium, but it drew complaints — especially from budget-constrained, small and medium-sized organizations — for its high hardware costs, manageability, questionable reliability, cost of media and unacceptably long restore times.

Backup Media

Over the last two years, disk has become more attractive as a backup medium. Its cost has been steadily shrinking and it offers the potential for faster backups and restores and greater reliability. Tape vendors began offering tape emulation software that enables companies to backup to hard drives in tape file formats. While this format helped resolve some challenges of real tape, it did not deliver the full potential of disk-based backups.

In promoting the move to disk backup, some storage vendors began offering CDP. They positioned CDP as a disk-based panacea that not only shrinks the backup window but also provides comprehensive restore capabilities. Backup software that is designed for disk is able to tap into the full potential of disk and offer more than tape emulation backup to disk. Yet CDP has not really taken off among small and mid-size businesses (SMBs).

In talking to SMB customers, whom we define as companies up to 1,000 employees, we found that they recognize the basic advantages of disk backup over tape, but found the official definition of CDP, as promulgated by the Storage Networking Industry Association (SNIA), somewhat daunting. It specifies that any backup technology that calls itself CDP must be able to restore any version of any stored file from any point in time.

A number of the SMBs didn’t feel that they wanted or needed the anything, anytime CDP restore functionality. To some, it sounded expensive and complex, and seemed like overkill. They pictured themselves faced with dozens of versions of a file, trying to decide which one to restore. What they needed and wanted was a disk-based backup solution that gave them continuous protection and a simple, more workable restore.

Continuous Protection: A Concept Becomes Reality

While disk-based data protection has been gaining ground over the last few years, CDP is now moving into the mainstream — and not simply as a solution for the challenge of today’s shrinking backup windows and restore reliability. It offers a real opportunity to rethink and revise how data protection is managed by organizations of all sizes.

The most widely used backup software now provides not only continuous protection for data, but a restore functionality geared to the needs of SMBs. It captures every file that changes immediately after the change. It also enables administrators to establish points in time during the day when the solution will take snapshots of the data — every hour on the hour, for example, or every two or three hours. When a restore is needed, the admin can choose from the desired previous version that has been protected.

Blogs and discussion forums have been abuzz about continuous data protection solutions designed to meet the needs of SMBs. These businesses can now restore not only the current version of a file, but also the version captured in its latest snapshot, whenever they want. Management is simpler. They are no longer plagued by questions of strategy about when and how to do full, incremental, or differential backups, as they were when they were doing backups to tape. They simply check a box in the software to backup files whenever they change, and the solution snapshots their data at configurable times.

No More Backup Window

This new solution also includes functionality that finally tames the backup window monster. Traditionally, when a file changed, its archive bit changed, and the backup software would detect it and backup the entire file — even if the change was as small as a single word or number. Backing up all the changed files from 10 or 15 file servers, one at a time, created backup windows that never seemed to end.

Using disk instead of tape improves backup performance in several important ways:

  • Block level changes mean faster protection. The software uses the operating system, not the archive bit, to instantly identify files that change. It also knows what part of the file has changed, and it backs up only that part. Consider: if the file is 5 MB, and only 100K of that has been changed, how much faster will backup be?
  • Simultaneous backups. The solution can backup all file servers at the same time. Instead of backing them up serially, waiting for one to finish before starting the next, you can configure any number of servers to backup simultaneously.
  • No more backup windows. The dreaded nightly backup window literally disappears, because backup is an ongoing process that provides continuous protection without interrupting production.

File Recovery

It simply takes too long to get a file back the traditional (and current) way, which is to call IT and request a file be restored. Typically this involves the IT Administrator searching through the catalog to find which tape the file is on, assuming the user or administrator know the file name and what version to search for. It might be that it’s in a full backup, which means multiple tapes to search. On the other hand, it might be part of an incremental or differential backup on subsequent tapes. The restore might take two or three tapes to get the full drive or the full directory back. And there may be no guarantee that the tape is even on-site. It is a long, manual, and not always successful process, given the reliability of tape in some circumstances.

There’s a better way. Let the users restore their own files with End User Restore. CDP solutions now enable the end user to retrieve files from a safe, secure location on the network using a standard Web browser. The end user simply pulls up their Web browser, goes to the Restore page, and uses a Google-esque search. They type in the file name and hit Search. The search engine within the continuous protection solution presents them with the files that match their criteria. They click on the one they want, hit Open, and in seconds they have the file they need.

End users rejoice to hear about this solution. So do IT people, because they don’t have to chase tapes, since the restore is done using a Web browser. This means no software to install clients on users’ PCs and no training on how to perform a restore. There is no fear that users may somehow corrupt the integrity of their backups. Users can’t alter files because the data is in a safe zone; they can only retrieve the files.

Bottom Line: Faster is Better, Continuous is Better

Time marches on, and so does technology. The bottom line is that there is now a pure disk-based backup/restore software solution available to SMBs, which:

  • Provides continuous protection for data
  • Blows away the backup window concept
  • Reduces administrative costs
  • Lets end users restore their own files.

The implementation of these tools is highly likely to make IT managers, administrators, and end users all much happier.


Brian Greene, is a Senior Product Manager with Symantec Corp.


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