A computerized method for migrating a tenant of a database system from a source database instance to a destination database instance, the tenant having tenant data stored in an immutable storage of the database system associated with a tenant identifier to be migrated to the destination database instance, the tenant data being stored in the immutable storage in a continuous order as extents, each extent having an assigned unique id, or key, the key including a tenant identifier to indicate which tenant the data is associated with, wherein the extents are ordered by the key, the immutable storage including metadata describing a physical storage location of the tenant data and an extent reference set defining where the extents are located in the physical storage location, the extent reference set containing extent identifiers and key ranges comprising a key start value and a key end value to define the extents that store corresponding data recorded continuously in the key range for each of the tenants, the method comprising: quiescing the tenant data of the tenant to be migrated from the source database instance to the destination database instance so that no new data is written to the storage of the database system associated with the tenant identifier at the source database instance; transmitting the metadata of the tenant to be migrated from the source database instance to the destination database instance without moving the tenant data in the storage, wherein the destination database instance is located on a physical server or virtualized server different from the source database instance, wherein the metadata of the tenant to be transmitted includes extent references to extents of the tenant data in the storage, key ranges of the extents, the tenant identifier data for the extents, and wherein at least one key of the key ranges includes the tenant identifier to associate the tenant with the tenant data; and modifying, at the destination database instance, the metadata of the tenant so that the destination database instance has access to the tenant data, wherein the modifying the metadata comprises adding at least one new extent reference that contains keys for the tenant being migrated from the source database instance to the destination database instance's active extent reference set. quiescing the tenant data of the tenant to be migrated from the source database instance to the destination database instance so that no new data is written to the storage of the database system associated with the tenant identifier at the source database instance; transmitting the metadata of the tenant to be migrated from the source database instance to the destination database instance without moving the tenant data in the storage, wherein the destination database instance is located on a physical server or virtualized server different from the source database instance, wherein the metadata of the tenant to be transmitted includes extent references to extents of the tenant data in the storage, key ranges of the extents, the tenant identifier data for the extents, and wherein at least one key of the key ranges includes the tenant identifier to associate the tenant with the tenant data; and modifying, at the destination database instance, the metadata of the tenant so that the destination database instance has access to the tenant data, wherein the modifying the metadata comprises adding at least one new extent reference that contains keys for the tenant being migrated from the source database instance to the destination database instance's active extent reference set.