Certainly, all data protection solutions have common basic requirements. Because these solutions use disk, they are often lumped together, painting a confusing picture of the data protection landscape.

– A new wave of disk-based solutions has entered the market to address longstanding challenges in enterprise data protection. Data will always need to be retained safely and securely; recovery should be possible with a reasonable amount of effort.

Using CDP, storage administrators can ‘roll back’ data storage systems to any previous point in time (within certain limits) rather than a predefined snapshot point. Continuous Data Protection (CDP) is an emerging technology designed to provide the same level of protection as snapshots but without the atomic point in time.

Questions remain regarding CDP technology’s integration with heterogeneous application environments and the real tangible benefit it offers over traditional snapshots.

Snapshot Technologies

* How easy is it to perform data recovery–for administrators and users?

When evaluating Staging solutions, it’s important to weigh the following criteria and consider:

Most technologies in this category enable data to be moved to tape at any time without disturbing business processes. Because of their cost, Staging devices are often used to keep the most recent backup data, typically for a few days maximum. Diskbased solutions in the Staging category include ATA arrays, Virtual Tape Libraries, Snapshot Technologies and Continuous – Data Protection. The cost of Staging solutions tends to be much higher than traditional tape; however, this is a secondary concern to speeding backups.

ATA Arrays

Continuous Data Protection

Since VTL solutions are intended to speed backups, it’s essential to examine the backup environment in its entirety.

VTL solutions tend to run faster than even ATA arrays, as no host operating system or file system is required. Virtual Tape Libraries are increasingly common; today no major tape library vendor remains without one in its product portfolio. Bottlenecks in application servers, media managers and software compression can often reduce throughput substantially; in some instances it may be sufficient or more cost-effective to use a traditional array. Most VTL solutions today also allow users to manage an attached tape library, backing up or restoring virtual tape images to real physical tape. VTL solutions add to the standard ATA array by providing an interface that mimics a tape library, allowing seamless integration into existing backup infrastructures with little or no process change.

Most modern storage systems support snapshot technologies in one form or another. Snapshot images can often be made end-user accessible, allowing users to locate previous versions of data or recover accidentally deleted files. Most snap-shot technologies tend to be reasonably efficient in their use of disk space, storing only changes to stored data rather than whole copies of changed files.

Snapshot technologies make a quick point-in-time image of the block-level storage or file system to be kept available to restore data, even when that data then subsequently changes. As the data is in a read-only format, the backup of a snapshot to tape is extremely simple.

Backup/Restore

Further, by breaking down your data protection requirements by segment, it becomes easier to set evaluation criteria and identify the right components for a complete solution. However, by examining key differentiating factors–including retention period, speed and cost–we can segment the data protection market into three areas: Staging solutions, designed for data kept briefly on the way to longer-term media; Backup/Restore solutions, designed for data kept in the medium term, when a restore will likely be required; and Archiving solutions, designed for data kept long term for legal or corporate requirements.

* What level of performance does it offer in meeting enterprise backup windows?

VTL Solutions

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* How well does it integrate with a disk library or tape library for longer-term retention?

Staging

* How well does it integrate with your existing backup software infrastructure?

ATA Arrays are used as target data repositories for backup operations. Backup to standard ATA Libraries tends to be extremely fast and easy to implement, but also extremely expensive. Most modern back-up software solutions from vendors like Veritas or EMC Legato support backup-to-disk options, in addition to – their more traditional backup-totape options. The cost per gigabyte for ATA array based storage in 2004 was between $3 and, $15 whereas tape storage was one-sixth that cost.

Enterprises typically keep up to six months of data for restoration in the event of data loss. Products in this segment tend to be a little slower than those in the staging segment; buying criteria is focused on reducing long-term data storage costs and enabling offsite data migration. Backup and restore products are typically at the core of a data protection solution. Disk-based products in the Backup/Restore category include Disk-Based Libraries and Capacity Optimized Storage. Tape libraries have been entrenched in enterprise back-up storage for many years. However, exponential growth in enterprise data, shrinking back-up windows and high-profile incidents of tape loss in transit have exposed the limitations of tape.

Further, studies show that one in three recoveries from tape fail–a rate of failure most organizations cannot tolerate.