Update Sequence Number

Update Sequence Number, сокр. USN
номер последовательного обновления
 In Active Directory replication, a 64-bit counter that is maintained by each Active Directory domain controller. At the start of each update transaction (originating or replicated) on a domain controller, the domain controller increments its current USN and associates this new value with the update request.
♦ The journal is disabled by default, and automatically enabled and used by the Indexing Service, File Replication Service (FRS), Remote Installation Service (RIS), and Remote Storage. Third party programs can also use the USN change journal.

— Игорь Мостицкий (обсуждение) 16:07, 9 января 2026 (MSK)