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ILM Changes Tape's Footprint

Ever since the term Information Lifecycle Management (ILM) began gaining traction in the storage sector, industry experts have stressed that ILM is an approach--not a product. ILM generally reflects the concept that the most cost-effective storage method is to use different types of media as the stored information ages. For example, transactional data that applications must readily access might be most appropriately stored on tier-one, high-end disk storage. When that data is ready to be archived, however, tape is typically more suitable and less costly.

However, if ILM is a concept, it's a concept that's implemented through products. And as the idea of ILM has been more aggressively embraced, it has had an impact on the development of new products. Over the past several weeks, product announcements from StorageTek and Quantum reflect the impact that ILM has had on current infrastructures and reveals a shift in the role of tape in backup and recovery operations.

Perhaps the key enabling technology for ILM has been the emergence of low-cost, high-capacity disk drives. These drives have let companies insert a new tier into the storage hierarchy. Instead of data moving directly from disk to tape for backup and recovery applications, data moves from online disk storage to near-online (or "nearline") disk storage. Disk-to-disk-to-tape infrastructures are increasingly common.

In turn, according to Mark Lewis, a senior product-marketing manager for Information Lifecycle Management solutions at StorageTek, the development of disk-to-disk-to-tape applications has led to a subtle shift in the role of tape in storage. Increasingly, administrators are using tape less for incremental backups and more for full backups and archiving. The reason is simple: Administrators consider disks more efficient for short-term backup and recovery. The window that disks require for incremental backup is smaller than the window that tape requires, and recovering specific data files from disk is also easier.

As low-cost disk arrays find a niche in backup applications, however, they can present several management challenges for storage administrators. According to Lewis, administrators don't want to manage nearline disk technology for backup and recovery the same way they manage their primary storage technology, for which they have to worry about allocating space and resources and accomplishing other tasks. Instead, Lewis argued, they want to manage those disks as if they were tape. Regardless of the specifics of the underlying hardware, administrators want the storage to look like one large pool that they can administer in a uniform, coherent fashion.

To that end, last week at Forum 2004--StorageTek's annual customer conference--the company offered end users a preview of its Virtual Storage Manager (VSM) for Open Systems. Based on the same intellectual property the company introduced for similar functionality in mainframe computing environments in 1999, VSM for Open Systems is a disk-based virtual tape library that applications see as high-performance tape drives. The product signals the emergence of a new management technology aimed directly at the relatively new, nearline tier in storage for backup and recovery, a tier that has become increasingly important as ILM has become a central organizing principle in storage. But as disk becomes easier to use for backup, where does that leave tape?

Increasingly, storage administrators are using tape for archiving and disaster recovery. That change is reflected in the product roadmap for DLT technology that Quantum announced at the end of September. The new product roadmap shows that, instead of focusing on speed and throughput, Quantum is focusing on capacity, cost, management, and security. According to Steve Berens, Quantum's senior director of product marketing and strategy, although manufacturers historically have competed heavily in the area of speed, in most applications tape drives have to slow down to match the data rates of incoming data. The primary criteria for speed, he suggested, is that the drive not become a bottleneck in the overall infrastructure. The new Quantum roadmap--which calls for the ability to store 10TB of data on one cartridge and projects multiple terabyte solutions for less than $1000--is consistent with the notion that administrators will be using tape less for incremental backup and recovery and more for full backups (generated by secondary disk storage), archiving, and disaster recovery. However, this change in tape's footprint doesn't mean that tape will become less important. Indeed, according to Jay Seifert, also a senior product-marketing manager for Information Lifecycle Management solutions at StorageTek, the introduction of technologies such as VSM for Open Systems might lead to increased tape usage. Many administrators, he noted, feel stymied by current technology, which doesn't let them back up all their data as frequently as they'd like. As moving data from primary to secondary storage becomes a more efficient process, administrators will be able to implement a more comprehensive backup strategy that lets them back up more data more frequently. Although the first steps in this evolution might be to disk, most of the data will eventually move to tape.

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