The type of data replication that is required for a hot-site disaster recovery model is constant. A hot site is a type of disaster recovery site that has fully operational IT infrastructure and equipment that can take over the primary site's functions immediately in case of a disaster or disruption. A hot site requires constant data replication between the primary site and the hot site to ensure that the data is up-to-date and consistent. Constant data replication means that any changes made to the data at the primary site are immediately copied to the hot site without any delay or lag.