Data migration
Post-migration: After data migration, results are subjected to data verification to determine whether data was accurately translated, is complete, and supports processes in the new system. During verification, there may be a need for a parallel run of both systems to identify areas of disparity and forestall erroneous data loss. Additional documentation and reporting of the migration project is conducted, and once the migration is validated complete, legacy systems may also be decommissioned. Migration close-out meetings will officially end the migration process.
Data island
A data island is a data store, such as on a PDA or other computing device, that has non-existent or limited external connectivity. This limits the ability of the user to synchronize with or copy the data to other devices. Though new data can be added to the system, the ability to move that data elsewhere is impractical or impossible. Data islands, in general, contain a very huge set of data relative to its small physical space that it occupies.