Disaster recovery: From cold to hot

Planning responses to disasters involves much more than scouting empty "cold sites" designed to await the unthinkable.

Disaster recovery technology is evolving rapidly, even stretching into the wireless world and into the nascent field of nanotechnology.

But as far as the more traditional backup sites are concerned, they differ in how connected they are to the central offices. Hot sites, for example, are facilities that are constantly connected to an agency's systems. They are usually hundreds of miles away from agency offices and are outfitted with all of the information technology assets needed in case of a disaster.

Cold sites, on the other hand, are facilities that periodically connect to agency systems for updates.

"It may be a warehouse owned by the organization," said Terry Rice, technical project manager for CACI International Inc.'s information assurance division.

According to Rice, most agencies have cold sites but are upgrading to warm sites, which are equipped with wide-area networking and other basic communications assets.

Also available are mobile backup sites, which are trucks or other outfitted vehicles that can be used on demand, Rice said.

Disaster recovery vendors are also increasing capacity-on-demand and mainframe-capacity-on-demand services, said Donna Scott, a vice president and research director at Gartner Inc.

The latter is "a box populated with more CPUs than you pay for that can be turned on three times a year for disaster recovery tests. The idea is that it lessens capital expense," she said.

The use of transaction replication techniques, such as mirroring and shadowing, is quickly advancing in disaster recovery technology. Mirroring is a disk-to-disk storage technology in which a record of a high-risk transaction, such as a wire transfer, is written automatically to a disk, Scott said.

Related to that is shadowing, a database technology that accomplishes much of the same task, but "doesn't work in lockstep," she said.

Deciding between shadowing and mirroring often comes down to the location of backup sites, she added. "When your two sites are far away, you must use shadowing. When the sites are close together, you can use either."

Mirroring vendors include Compaq Computer Corp., Hewlett-Packard Co., Hitachi Data Systems, IBM Corp. and SRDS. Shadowing solutions are offered by Oracle Corp., Hitachi and others. Meanwhile, companies such as Veritas Software are offering such solutions in a hosted environment.

Networking and wireless advances have catapulted technologies such as wireless local-area networks built around standards such as 802.11 and Bluetooth into the field of disaster preparedness planning, said CACI's Rice.

Along with pushing the idea of having traffic jetted onto wireless LANs and fixed wireless networks in the event of a disaster, vendors are also playing up routing technologies such as Multilabel Protocol Switch.

Finally, the destruction incurred during the Sept. 11 attacks is also stirring interest in embedding chips in IT assets. Use of such nanotechnology could allow federal users to track the health and status of devices involved in a disaster, Rice said.