Don't rule out tape, experts say

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

In the aftermath of the Sep. 11, 2001 attacks, the talk is ofever-greater need for disk to provide immediate disaster recovery forbusinesses. Though the price of disk storage is falling, analysts do notexpect disk to match the price performance of tape.

Gartner Group claim that the typical cost of enterprise disk storageamounts to US$110 per G-byte, whereas tape costs $11 per G-byte. Gartnerpredicts an 80 percent possibility that this disparity will remain until2007.

Analysts at International Data Corp (IDC) insist that disk prices willnever approach the levels of tape. "The cost per gigabyte for tape is solow and getting lower with improving capacity," said Martin Wijaya,senior analyst for storage at IDC Asia-Pacific. "It's also moreexpensive to manufacture a disk that reaches the density level of tape."

At Storage Technology Corp. (StorageTek), the belief is that despitebusiness continuance driving the need for disk backup due to disk'sfaster access to data, the role of tape is undiminished. "However validit is to make the first backup to disk--this merely delays the point atwhich you backup to tape," said Rob Nieboer, tape business manager forAsia Pacific and Latin America at StorageTek.

To minimize potential business downtime, backing up to disk is a goodidea, agreed Nieboer. "People will and should be doing that (backing upon disk)," he noted. "But if anyone thinks that this can be applied toall storage needs, they simply have rocks in their head or have alimitless budget."

Nieboer is adamant that tape is the only cost-effective medium that canback up data, then be physically removed and located elsewhere. Wijayasaid that disk will not replace tape, as tape-based storage provides anadded value with its portability, "but with disk, you have to keep itonline all the time."

Both Nieboer and Wijaya agreed on a storage lifecycle where both diskand tape have their defined roles, with disk-based storage typicallyused for initial backup of mission-critical applications and data forbusiness continuance, with additional tape backup optional. As that databecomes less active, it is migrated to cheaper forms of disk untilfinally residing on tape when real time access to that data isnon-critical.

Wijaya noted that the role of tape storage has certainly moved to ahigher importance. "Given recent crises and disasters, users are askingmore intelligent questions when it comes to tape," he said. As ITbudgets tighten, "implementing tape for backup and archiving is morefeasible than implementing a remote disaster recovery site, forinstance," he added.

Nieboer also observed that many traditional companies are digitizingtheir data for future reference and--in many cases--may not require highspeed access. "People who are doing document imaging may require tapestorage," he noted.

Search and retrieval enabling in image and document archives are key forgovernment agencies and older large corporations with masses ofdocumented data.

He also pointed to the broadcast industry as potential tape enthusiasts.

"(in the case of) content conversion to digital format for suchcompanies, even at a 10-to-1 price differential, disk won't be cheapenough," said Nieboer.