An essential part of business continuity is the use of alternative sites. Using remote sites can provide more robust disaster recovery solutions for businesses. Multi-site business continuity plans rely on backup sites where companies can quickly relocate their IT infrastructure if the primary site goes dark. For this purpose there are three types of data backup sites an organization can put into place.
Cold Sites — The least expensive of the backup site options, cold sites are essentially buildings with connectivity but without hardware. For businesses, these stand-by sites are the cheapest option, providing a location to set up intermediary operations while primary sites are restored. This means operations at the new site need to be “warmed up”, and hardware installed, configured, otherwise brought online and capable of serving.
Hot Sites — Hot sites essentially are duplicates of production systems, running in parallel, waiting to take over should there be a disaster that hobbles the main system. These systems synchronize in real-time, making them expensive yet highly resilient. For critical industries like healthcare and finance, hot sites are essential for business continuity.
Warm Sites — Warm sites occupy the continuum between hot and cold sites. These systems duplicate production systems set to a schedule. To optimize expense and administration, primary site backups to warm sites are performed on a cycle, perhaps daily, or weekly. If disaster should occur, then current systems can be restored to the most recent backup.
Hot sites provide the fastest recovery time, while cold sites are the least expensive to initially set up (though perhaps costly in time when responding to disaster). Warm sites provide some wiggle room between, but these decisions are typically based on an organization's acceptable recovery time objective (RTO), or the duration allowed between an outage and restoration of main systems.