Backing up to external hard drives: cost-effective for SMB.

Inexpensive, external hard drives can play an important role in the backup process for a variety of business environments. Backing up to external hard drives is a cost-effective, easy-to-manage strategy that allows companies to store vital data in a secure offsite location for disaster recovery purposes. External hard drive backup fills a persistently under-served SMB market gap, and offers a clear alternative for users who do not wish to implement more expensive high-end tape solutions.

Cost Effective

Backing up to external hard drives is cost effective for environments with backup loads of less than 400GB. For example, two external 250GB hard drives can be implemented for about $700. An equivalent tape system would cost at least $2500 for an autoloader and $600 for two sets of media, for a combined cost of $3100 or more. This does not include the cost of management software, installation and setup, and the time required to learn a tape system.

Figure 1 looks at the relative capacity requirements of a variety of environments. The market segment, which must accommodate data loads of 80GB-300GB, is best served by disk-based backup. This encompasses a broad range of operations including small and mid-size businesses, departments and workgroups within larger enterprises, and remote offices of larger companies.

Easy to Manage

Current tape users know that the larger the data load, the more hands-on management a tape drive requires. But because a high-capacity external hard drive can hold more data than a typical tape, backups to a hard drive can run unattended without requiring the manual insertion of additional tapes or the purchase of a more costly tape autoloader. Rather than juggling and tracking a half-dozen or more tapes using a complex tape rotation scheme, backups can be stored on two or more external hard drives. This is a major benefit in small businesses and remote offices where there may be no IT staff.

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As shown in Figure 2, one drive remains on site for performing backups. The second drive is stored securely off site for disaster recovery purposes. The two hard drives are switched periodically to update the off-site data and to protect the recent data by moving it off site.

Advanced Data Protection

Full-featured backup software for these environments adds advanced data protection to disk backup systems. Drag-and-drop, mirroring, and disk duplication might provide adequate protection for personal users with minimal data by transferring certain files to the external hard drive, but they typically do not provide the following important business-class backup attributes:

* Retain past versions of files and folders: Backups must allow for the recovery of multiple past versions of files and folders in order to recover data that was inadvertently deleted or somehow damaged.

* Incremental backups: To save time, backup software must provide fast incremental backups, which only need to capture new and changed files. Drag-and-drop or disk duplication strategies are time consuming because they usually copy all of the files and folders each time, often exceeding the backup window.

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* System state: In addition to protecting files and folders, a business-class backup solution must protect device drivers, the Windows registry, operating system settings, and applications and their settings.

* Networked computers: Protection should be available for networked computers including those that run the popular Windows, Macintosh, Linux, and Solaris operating systems. Protection should encompass file servers, desktops, notebooks, and 24X7 applications (for example, Exchange Server and SQL Server).

* Scheduled backups and backup reports: Backup administrators must be able to schedule automated backups and receive easy-to-understand backup reports that make the backup review process painless.

Onsite/Offsite Media Rotation

External hard drives can be easily transported off site to protect data from disasters such as flood, fire or earthquake.

Most backup software is designed around the assumption that tape will be used as the final storage media, and then rotated off site. This makes it inappropriate for external hard disks because the software uses complex and unforgiving strategies to use and track the tapes and rotate them off site.

For example, with the commonly used grandfather-father-son strategy, two weeks of daily backups may be done with 8 son tapes. During the third week the administrator can reuse the first week of son tapes for daily backups. Father backups, which are time-consuming full backups, are done for 3 consecutive weeks before the media of the oldest father backup is reused. Grandfather backups are monthly full backups, which must also be performed and retained for the system to work. Matters are further complicated by the need to keep tapes on site for restores, and off site for disaster protection. This is all too much for any business that does not have dedicated, trained, professionals to execute the backup strategy.

Because these tape rotation strategies are built into the design of most backup software, the software cannot back up to external hard drives unless it treats each drive as a tape. This requires purchasing far more external hard drives than are necessary, and does not solve the difficulties of grandfather-father-son scheduling. This is an expensive and impractical solution, especially for a small to mid-size business that could use Retrospect and easily store data on two external hard disks.

Conclusion

For companies whose backups fit onto one or more external hard drives, there is now an alternative that is more convenient than manually using multiple low-end tapes in a single tape drive, and more cost-effective than investing in a tape autoloader. However, most backup software lacks key capabilities that are necessary for backing up to external hard drives. Only Dantz Retrospect has features that work optimally with external hard drives, allowing small companies to make the best use of their personnel and financial resources to implement a backup strategy that meets their needs for ease of use, budgetary concerns, while maintaining reliable data protection for on site and off site disaster recovery.

Don Chouinard is director of product management at Dantz Development Corp. (Walnut Creek, CA)

www.dantz.com