There are two common definitions for the phrase data migration: Translating data and moving data.
(1) Translating Data
Data migration is used to describe the process of translating data from one format to another. Data migration is necessary when an organization decides to use a new computing systems or database management system that is incompatible with the current system. Typically, data migration is performed by a set of customized programs or scripts that automatically transfer the data.
(2) Moving Data
Data migration is a phrase used to describe the process of moving data from one storage device to another. In this context, data migration is the same as Hierarchical Storage Management (HSM).
