Tape Roadmap by Information Storage Industry Consortium

The new 2011 International Magnetic Tape Storage Applications & Systems Roadmap is the culmination of a yearlong effort, led by Information Storage Industry Consortium‘s Barry Schechtman, Executive Director Emeritus and Technical Director for INSIC’s TAPE Research Program, and which involved the participation of representatives of Hewlett-Packard, IBM, Imation, Oracle, Quantum, Spectra Logic and Symantec, as well as inputs from industry analysts and applications experts in various fields.

The report delivers an optimistic outlook for tape storage going forward. However, it also said that this optimistic outlook will be fulfilled only if the tape storage industry continues to invest in the research and advanced development necessary to provide the future technologies that are needed.

Despite predictions by some of the demise of tape storage as a result of competitive pressure from disk technology, tape is much alive and reestablishing its strong identity as a storage medium that can provide many benefits, particularly in the context of long-term preservation of data. Tape has been shifting from its historical role of serving as a medium dedicated primarily to short-term backup, to a medium that addresses a much broader set of data storage goals, including active archive (the most promising segment of market growth), regulatory compliance (approximately 20% – 25% of all business data created must be retained to meet compliance requirements for a specified and often lengthy period), and disaster recovery, which continues in its traditional requirements as a significant use of tape. With the advent of the cloud, and the inherent consolidation of data into large systems that cloud storage implies, another category for tape applications is emerging: transport – moving data to and from the cloud for organizations with large quantities of data.

Recently developed tape storage features, such as encryption, and technologies like LTFS (Linear Tape File System), for facilitating file access, increase the suitability and attractiveness of tape for these broader aspects of use (that is, beyond backup), including and perhaps especially active archive, along with compliance and disaster recovery. Further, there is a gradually growing appreciation in both the storage technology and storage user communities that backup and archive applications are not the same: they have different objectives and therefore impose different requirements on the storage systems that they utilize. To make optimal use of tape requires configuring storage systems for various use cases and matching the data uses to media type. Tape’s specific advantages include low acquisition cost, low operational costs (power, cooling, and staffing), high data reliability, longevity of stored data, data portability, and high streaming rates. For some data, such as data retained for compliance or data in certain scientific computing environments, tape may provide the best repository, even as the primary storage target.

An important element of appropriate storage systems configuration is to provide tiering that distinguishes use categories of data and matches the use to a specific type of storage media. This optimizes the price/performance of the system, putting only data that requires fast access on the more expensive tiers, and placing data that does not require fast access on the lowest cost tier – tape. Disk can also be used as a buffer to optimize the performance of the system,i.e. moving data to disk and then streaming from disk to tape. The way in which tape is implemented in a tiered storage system is dependent on the function(s) for which the tape is used.

The following examples of tape use assume
a multi-platform storage architecture
that includes both disk and tape:

• For backup and recovery tasks, tape has largely migrated to a third tier, using a disk-to-disk-to-tape architecture. Analyst studies indicate that 95% of data recovery occurs in the first two weeks following data creation, making disk an ideal short-term storage medium, given disk’s random access capabilities. Tape provides low-cost, high reliability storage for data that is less frequently accessed.
• For DR, tape contains the primary data source, which has been one of tape’s traditional uses. DR is typically executed in tiered storage as a tier three function. As above, tape provides low-cost, high-reliability storage for infrequently accessed data, and it has the advantage of being highly portable, making it very straightforward to keep one copy in a location away from the data center site. Further, tape is fast in streaming large quantities of data, making it ideal for disaster recovery – which typically requires restoration of a considerable amount of data.
• For active archive – that is, data that has moved from primary disk – the tape copy serves as the primary copy. This permits all data to be accessible all the time. Typically the data moves to tape as tier 2 or tier This reflects a trend to increase tape’s use for nearline retrieval of information that is less actively accessed than the information kept on disk. Tape is more reliable than disk, has a much longer archival life, and much lower power and cooling requirements. It requires a few minutes of latency in retrieving data – two minutes or less, typically, in contemporary tape automation systems.
• For compliance, tape is the medium of choice, along a path through the storage hierarchy that includes two tiers of disk before the data moves to tape in a tertiary tier. Given tape’s long storage capabilities and high reliability, along with low cost, tape is an ideal medium for storing data over the long term to meet compliance objectives.

Tape’s role in the cloud is significant. From a practical point of view, a copy of all or most data stored in the cloud on disk is typically migrated to tape, if only to address incidents that put data stored exclusively on disk at risk of loss. Tape is also used in cloud storage environments to address the storage provider cost issues, as tape is less costly than disk in terms of both initial capital expenditure and ongoing operating expenditures. Tape’s low energy usage contributes a significant factor to its cost advantage, as well, and one that is growing in importance. In addition, numerous vertical markets, for which the attributes of tape storage provide an excellent fit, are currently developing their archive strategies for data preservation; Examples of such markets include media broadcast and entertainment, health care, geologic exploration, video surveillance and criminal justice.

Tape technology has continued to advance impressively in the past few years, and despite forecasts that tape drive and media revenues and unit shipments may decline somewhat, tape is expected to retain a very significant share of worldwide stored data. As part of the continuing digital data creation explosion that is well documented, the amount of data kept on tape is expected to grow at a CAGR of 45 % from 2010 through 2015.

               Projected Growth of Data Stored on Tape

                  (Source: Enterprise Strategy Group)

Keeping media costs low and continuing to advance tape technology, both in information density and data transfer rate, are critical to the future success of tape storage. Recent laboratory demonstrations indicate that tape has the potential to further improve its technology by at least an order of magnitude, and unlike disk, is still far from approaching any fundamental density limitations. Also, paths to even greater densities on tape, approaching 100 Gbits/in², have been discussed and appear promising. However, advancing tape technology will require addressing numerous difficult materials and device engineering challenges, which will require continuing investment by the tape industry in R&D.

In addition to engineering advances in the underlying drive and media hardware technologies, it is expected that suppliers of tape storage systems and their automation will continue to address user concerns as tape capacities continue to grow.

Important aspects include:

• Increasing accessibility of the data on tape – one possibility is to have more partitioning/meta-data on tape – so that tape is easier/faster to navigate.
• Moving from custom software application tape formats (for example, used by many backup applications) – to a more generic file system front-end (such as LTFS), so that data can be read from tape just as it is from disk.
• Simplifying data migration processes – to new generations of technology.

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