Backup strategies: Strengths and weaknesses

Backups can guard against data loss, support compliance and retention needs and protect the business from disaster. But good backups need much more than a new tape library or the latest software release. Backups need a clear plan that meets the objectives of your specific business. Backup windows and RPOs must be met, and the backups must be recoverable within established RTOs. To accomplish these objectives and others, storage administrators must develop and maintain a solid backup strategy that protects relevant data in a timely manner using the appropriate backup platform.

Backup strategies -- Strengths and weaknesses

There is no single backup strategy --- each organization must formulate a strategy that meets its unique backup, compliance or disaster recovery needs. The problem is further complicated by a variety of data types that must be treated differently, usually involving a mix of products to support several backup priorities.

Products and tools

A well-formulated backup strategy should consider the specialized disk storage platforms that are available. Virtual tape libraries (VTL), content-addressed storage (CAS) and continuous data protection (CDP) are three principle disk storage systems that can address specific backup needs.

Time proven backup methods like tape continue to work adequately in some situations, but analysts agree that disk-based technologies are systematically displacing tape-based systems for primary backup tasks. "Use disk in some part of your backup strategy, even if only for your most critical application data, since the benefits you will experience will far outweigh the pain and overhead associated with backing up and managing tape cartridges on a daily basis," says Jerome Wendt, independent storage analyst. Although disk-to-disk platforms are expected to remain more expensive than tape on a cost per gigabyte basis, they offer better backup, and restore performance and eliminate the common problems of failed backups and tape management.

Also, opting to back up directly to current tape drives can be terribly inefficient because the drives offer throughput capabilities that are several times higher than the throughput of a typical backup server. For example, an LTO drive with compression can handle throughputs around 160 MBps, while an average backup server will only supply about 50-60 MBps. This speed disparity results in wasted tape drive acquisitions and unrealized backup performance.

A VTL platform can directly replace a tape library while utilizing existing backup software and policies. Archiving data to CAS can move data off of primary storage, reducing the amount of data that has to be backed up in the first place [see the article on CAS here]. Snapshots allow for more frequent restore points. CDP can protect mission critical data in real-time with essentially no backup window and a restore point up to the moment. The trick is to select one or more technologies that accommodate your business needs.

Storage administrators should also leverage tools to assist in strategic planning. "Take the time to inventory your environment in terms of hardware and software using one of the emerging storage analytic tools because it is almost impossible to come up with a strategy if you do not know what you have or how you are using it," Wendt says. There are several classes of software tools to consider. Monitoring tools from organizations, like Bocada Inc. and WysDM Software Inc., keep track of existing backup jobs and report on their status. This provides administrators with important tactical details of daily backup operations. Problems with backup jobs or snapshots can be identified and addressed in a timely manner.

Storage resource management (SRM) tools provide backup strategists with important insights into their storage environment and configuration. However, the choice of SRM tool can be confusing because there are numerous vendors, including the CA Inc., EMC Corp. and Hitachi Data Systems Inc., and many products are designed around specific hardware platforms rather than heterogeneous environments. Storage analytics tools offer features similar to SRM -- gathering information about the physical and logical assets across an environment and distilling that information into a form that can help organizations make choices about those assets.

Data classification tools are also growing in importance, allowing backup strategists to see the data resources that are present in the environment and categorize data for more effective backups. Companies like Kazeon Systems Inc., Abrevity Inc. and StoredIQ are just three developers of data classification tools [see the article on data classification here].

Analysts warn against the broad deployment of encryption technologies as part of a backup strategy. "While encrypting data on a case-by-case basis makes sense, there are still too many unknowns and variables associated with encrypting all data," Wendt says. Key management remains a crucial concern, while deployment choices (e.g., encryption may be integrated in backup software, in hardware-based appliances or directly within the tape drive itself) can vastly impact pricing and performance.

Keeping the plan updated

Once a backup strategy is formulated, it should be revisited periodically and updated to reflect changes in the organization. Just how often should those updates be? Depending on whom you ask, the answer varies anywhere from "once a quarter" to "no less than every two years." Ultimately, any backup strategy should change to reflect changes in your storage infrastructure.

Backup strategies cannot be developed or re-evaluated in a vacuum -- it normally involves several disciplines from across the organization. An architectural group defines the scope of the backup strategy and identifies relevant applications. A technical committee of capacity planners, system administrators, database administrators, storage administrators, application owners and network engineers should collaborate to ensure the right data is backed up at the right time, and that the infrastructure will support the proposed strategy. There should also be a financial/legal committee to identify the importance of each application, the cost of being without that application and the potential penalties or liabilities involved with the corresponding data. This combination of disciplines is essential to develop a backup strategy that will protect the enterprise.

Go to the next part of this article: Backup strategies: The vendors

Or skip to the section of interest:

  • Introduction
  • Backup strategies: An overview
  • Backup strategies: Strengths and weaknesses
  • Backup strategies: The vendors
  • Backup strategies: User perspectives
  • Backup strategies: Future directions

  • Dig Deeper on Disk-based backup



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