1.3 Services and Components Used by DFS

DFS junctions can reside only on NSS volumes. The DFS volume move and split options are available only where both the source and destination volumes are NSS volumes.

DFS junctions can also point to NCP volumes (NCP shares for Linux POSIX volumes). NCP Server must be installed and running on the target server in order to support NCP volumes. It enforces secure file access on NCP volumes for Linux-enabled eDirectory users, using the Novell Trustee Model of trustees and trustee rights.

When you define an NCP share (mount point) for the NCP volume, NCP Server creates a Volume object in eDirectory. DFS assigns a DFS GUID as an object attribute for the NCP volume. The physical server location of the NCP volume is tracked in the VLDB. The VLDB tracks volumes by their DFS GUIDs and does not contain information that distinguishes whether a given volume is an NSS volume or an NCP volume.

DFS uses Novell Storage Management Services to copy files to the new location in a DFS volume move or split. An SMS copy is faster than for a normal copy utility, and it can be restarted as needed.

The VLDB code is written to Novell eDirectory, not LDAP, and uses the low-level DClient interfaces for eDirectory. This requires that eDirectory be running on servers that contain junctions or on both the source and target servers when using the DFS volume moves or splits. However, an eDirectory replica is not required to be co-located on the server.

JetStream provides a transport-independent interprocess communication facility. DFS uses JetStream for interprocess communications by DFS modules. JetStream uses an unregistered TCP port 6901 (0x1AF5). This port assignment is not configurable. Using DFS through a firewall requires this port to be opened by the network administrator. DFS components that interact with JetStream use eDirectory names (such as dfstest.east.example) for names of target hosts. The DFS JetStream-related code uses the low-level DClient interfaces for eDirectory.