Don’t rule out tape, experts say

Traditional vendors of tape-based storage have no fear from disk-based systems usurping the role of primary backup and data archiving medium, say experts.

In the aftermath of the Sep. 11, 2001, attacks, the talk is of ever-greater need for disk to provide immediate disaster recovery for businesses. Though the price of disk storage is falling, analysts do not expect disk to match the price performance of tape.

Gartner Group claim that the typical cost of enterprise disk storage amounts to US$110 per G-byte, whereas tape costs $11 per G-byte. Gartner predicts an 80 percent possibility that this disparity will remain until 2007.

Analysts at International Data Corp (IDC) insist that disk prices will never approach the levels of tape. “The cost per gigabyte for tape is so low and getting lower with improving capacity,” said Martin Wijaya, senior analyst for storage at IDC Asia-Pacific. “It’s also more expensive to manufacture a disk that reaches the density level of tape.”

At Storage Technology Corp. (StorageTek), the belief is that despite business continuance driving the need for disk backup due to disk’s faster access to data, the role of tape is undiminished. “However valid it is to make the first backup to disk–this merely delays the point at which you backup to tape,” said Rob Nieboer, tape business manager for Asia Pacific and Latin America at StorageTek.

To minimize potential business downtime, backing up to disk is a good idea, agreed Nieboer. “People will and should be doing that (backing up on disk),” he noted. “But if anyone thinks that this can be applied to all storage needs, they simply have rocks in their head or have a limitless budget.”

Nieboer is adamant that tape is the only cost-effective medium that can back up data, then be physically removed and located elsewhere. Wijaya said that disk will not replace tape, as tape-based storage provides an added value with its portability, “but with disk, you have to keep it online all the time.”

Both Nieboer and Wijaya agreed on a storage lifecycle where both disk and tape have their defined roles, with disk-based storage typically used for initial backup of mission-critical applications and data for business continuance, with additional tape backup optional. As that data becomes less active, it is migrated to cheaper forms of disk until finally residing on tape when real time access to that data is non-critical.

Wijaya noted that the role of tape storage has certainly moved to a higher importance. “Given recent crises and disasters, users are asking more intelligent questions when it comes to tape,” he said. As IT budgets tighten, “implementing tape for backup and archiving is more feasible than implementing a remote disaster recovery site, for instance,” he added.

Nieboer also observed that many traditional companies are digitizing their data for future reference and–in many cases–may not require high speed access. “People who are doing document imaging may require tape storage,” he noted.

Search and retrieval enabling in image and document archives are key for government agencies and older large corporations with masses of documented data.

He also pointed to the broadcast industry as potential tape enthusiasts. “(in the case of) content conversion to digital format for such companies, even at a 10-to-1 price differential, disk won’t be cheap enough,” said Nieboer.