A hot site is in direct contrast to the cold site in terms of functionality. It is a backup facility that is fully operational and is equipped with the necessary hardware, software, telecommunication lines, and network connectivity to allow an organization to be up and running almost immediately. A hot site will have all required servers, workstations, and communications links and can function as a branch office or data center that is online and connected to the production network.
In addition, a backup of the data from the systems at the primary site is held on servers at the hot site. This can be a replication copy of the data from production servers, which may be replicated to the hot site in real time, so an exact duplicate of the systems are ready if and when required. The data can also be stored on the servers with the most updated information available from replicated copies.
Hot sites greatly reduce or eliminate downtime for the organization. The disadvantage of this type of facility is cost. Maintaining a fully functional hot site essentially doubles the organization’s budget for hardware, software, and services and requires the use of additional manpower to maintain the site.
A cold site is a facility that is large enough to handle the operational load of the organization and has the appropriate electrical and environmental support systems. The drawback is a cold site is void of online computing facilities, does not have active broadband communications links, and has no part of the production network. A cold side may have a portion of needed equipment to resume operations but it would require installation time for the data to be restored to servers.
Because it has no operating computing base or communication links, a cold site is inexpensive to maintain as it doesn’t require maintenance of workstations and servers. The challenge is the amount of time and work involved to set up fundamental resources for the site to be fully operational.
A warm site is the middle ground between a hot site and a cold site. Although it’s not as well equipped as a hot site, it has a portion of the necessary hardware, software, data circuits, and other resources needed to quickly restore normal business operations. This equipment is usually preconfigured and primed to run appropriate applications to support the organization’s operations. Though there is not data replication to the servers and a backup copy is not available. In this case the bulk of the data must be taken to the site and restored to the standby servers.
Activation of a warm site typically takes 12 hours from the time a disaster is declared. However, warm sites avoid the significant telecommunications and personnel costs inherent in maintaining a near-real-time copy of the operational data environment.
A mobile site is one or more self-contained trailers that have all of the environmental control systems necessary to sustain a safe computing environment. Larger corporations sometimes have these sites on a ”fly-away” basis, ready to activate and send them to any operating location around the world via air, rail, sea, or surface transportation. Smaller firms might negotiate with a mobile site vendor in the local area to provide these services on an as-needed basis.