IP migration is the migration of servers between locations. These locations may be physical changes in location or virtual address changes. The IP migration must be properly managed as the server addresses are not updated throughout the Internet for up to 48 hours in certain instances. As such, most IP migration changes are scheduled for a period of consecutive non-business hours.
Some organizations may implement their IP migration over a weekend when the company will be closed for a long period. Others may have to set a specific outage time frame in which to manage a migration. If the company has mission critical data that must be moved in an IP migration process, the company may make a duplicate of such data first. Once the data has been duplicated, then the migration process may use the duplicate data for the mission critical processes and move the original data set. After the original data set has been migrated, then the mission critical process is reset to use the original data set location rather than the copy, which finalizes the migration for that data set.
The planning process for the IP migration should take into consideration the order in which the servers are to be moved. For example, one process may access several servers for data. Each of the servers accessed in that process should be moved within the same basic time period so that all are in their new locations when the process is run the next time. The complexity of the planning process is roughly equivalent to the number of servers and processes affected by the move.
If the IP migration is small or isolated, an organization may choose to make the move during business hours. This decision might also be made when the servers being migrated do not support mission critical applications. When the migration affects only ancillary applications, an organization has much more flexibility in scheduling. Frequently, an organization may schedule non-mission critical IP migrations over a period of weeks during business hours so that the technology staff may work on these moves during regular work hours. This reduces the cost of such IP migration because overtime hours are limited.
The Domain Name System (DNS) used by the Internet as its telephone book in finding servers has up to 48 hours to update the server’s new location; however, in many instances, the update occurs very rapidly. Sometimes a Web site’s server address may be changed in the morning and the DNS recognizes it by early afternoon. In other cases, however, the change may not be recognized for at least 48 hours. The time period in which the change is recognized depends largely upon the amount of activity that occurred immediately prior to and during a change.