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As IT data centers begin to embrace disk as a viable medium in secondary storage, virtual tape libraries (VTLs) fill an important niche between primary storage and archival storage on tape.
Disk in the form of VTLs?that is, di sk presented as tape?can be added without requiring huge changes to existing backup strategies. This compares favorably to adding disk into an existing environment, because adding disk without the VTL interface requires complex and unavoidable changes to existing strategies. This simplicity, coupled with the affordability of SATA disk for short-term storage, has turned VTL into a viable storage option. First generation VTLs are gradually moving into data centers.
First generation technology typically has drawbacks?a useful new technology, or a new variation on an existing technology, is almost certain to have problems. By virtue of being new, a product offers options to users that weren?t there before. It takes time to integrate new technology, and with field-use, technological and usability issues become evident. The technology can then be refined, taking it to the next level.
First generation VTLs do have problems, primarily complexity of setup. Secondarily, and perhaps directly related to complexity, VTLs often have problems with the real-world performance versus theoretical gains. Spectra Logic?s RXT Sabre addresses all the first generation VTL drawbacks and consequently goes a step further, adding features that expand beyond first generation VTL (disk-as-tape) products.
VTL: Many Advantages
The advantages that VTLs bring to secondary storage have led to the increasingly widespread deployment of VTLs in backup environments.
Increased Reliability and Performance
Backup Environment Continuity
Easier to Implement than Disk-as-Disk
Easily Scaled
VTLs are establishing themselves as valid backup storage options. The first generation of VTLs took some years to earn this validity. As with all new technology, however, field-use has brought to light some disadvantages associated with typical VTLs.
Spectra Logic?s RXT Sabre as VTL provides an extremely intuitive and practical implementation of VTL, addressing the shortcomings of first generation products while expanding the flexibility and advantages this solution provides.
The Spectra T950 library with RXT Sabre VTL and tape is particularly illustrative of the value of Spectra Logic?s unique andcomplete data protection solutions. By incorporating RXT SabreDrives, SabreMedia, tape drives, and tape cartridges into a single Spectra T950 library, administrators gain simplicity while taking full advantage of VTL. Further, because SabreDrives and SabreMedia can be scaled independently of each other, RXT Sabre gives administrators the option of expanding capacity, performance, or both, rather than requiring data centers to pay for both in lockstep, as is the case with traditional VTLs.
Finally, although the tape is virtual, SabreMedia are physical, bar-coded packs, making it easy to find data that needs to be restored. These advantages help VTLs step up to their initial promise in simplifying the addition of disk, with its reliability and performance advantages, to any backup environment.
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