This article can also be found in the Premium Editorial Download "Storage magazine: How to distance your data from disaster."
Download it now to read this article plus other related content.
|What's a 'super tape'?|
The term "super tape" is often applied to a group of tape formats, including 3592, 9940, AIT/SAIT, DLT/SDLT, LTO and StorageTek T10000, which are approaching 1TB native capacities. The following minimum characteristics roughly define the super tape category for 2006.
Native maximum capacity of 400GB. With disk becoming the primary target for backups, enterprise users can now take advantage of the larger tape capacities to minimize the number of tapes they manage.
Native maximum transfer rate of 50MB/sec. Data transfers from disk to tape can occur at faster transfer rates without errors.
Media form factor of 8mm or a half-inch. Larger media form factors of 8mm or a half-inch support the additional tracks required for higher capacities and transfer rates.
WORM option. The option to purchase or convert tapes so they store data in an unalterable format should be viewed as a necessity for users with compliance requirements.
Tape's actual cost
The final reason to use--or not to use--a higher capacity tape is financial. DLTtape S4 delivers roughly double the native capacity of SAIT-1 and LTO-3 for approximately the same price. However, buying tape based strictly on the cost per gigabyte doesn't take into account other cost-related issues, such as the need to upgrade tape libraries. Managing data on larger capacity tapes may also be a concern. "Capacity is getting so large that users can't use all of the space on the tape," says Richard Leonarz, marketing manager for tape storage in Sony's Media & Applications Solutions Division. Each succeeding generation in the "super tape" category becomes quicker and holds more data in a Sisyphean effort to keep up with growing data stores (see "What's a 'super tape'?").
But jamming more bits onto a tape introduces new compatibility and usage problems. LTO-3 tape drives can read and write LTO-2 and LTO-3 tape cartridges, but read only LTO-1 tape cartridges. SAIT-1 and StorageTek T10000 tape drives can only read and write to their respective SAIT-1 and T10000 tape cartridges; they can't read or write from older AIT, 9840 and 9940 tape formats. And as tape capacities and data transfer rates increase, users need to ensure that the tape drives supporting these formats can adjust tape transfer rates to match the slower speeds and feeds their infrastructure will likely produce.
This was first published in May 2006