Planning and Configuring HP-UX DCE 2.0

Configuring HP-UX DCE Cells
Integrating DCE Services with HP Serviceguard
Chapter 668
The Security and Naming services replicate only their read operations.
That is, while a client can choose between any of the replicas to obtain
information, it must go to a specific replica — the master replica — to
perform a write operation. The master replica is then responsible for
informing the other (read-only) replicas of the change.
While the replication mechanisms of the Security Service and the
Naming Service differ in design and implementation, they share this
master-slave approach. Therefore, while both services can be considered
highly available for read operations, they do present a single point of
failure for write operations.
The Time Service, on the other hand, does not present the same level of
vulnerability. Most mission critical installations will configure more than
the minimum necessary time servers with multiple time providers. This
being the case, the loss of a single time server is usually not critical.
Installations should not establish an HP Serviceguard configuration for
the purpose of maintaining the Time Service alone.
DCE-based applications can also present a single point of failure, unless
the developers provide for the replication of data and functions between
multiple servers. Since replication is a complicated and complex process,
many application designers may choose to depend on a "fail over"
approach such as HP Serviceguard to provide availability, rather than
develop and maintain their own replication mechanisms.
In summary, you only need to use HP Serviceguard to increase the
availability of DCE Core Services and DCE-based services that are not
replicated. In the case of the DCE Core services, these are the write
functions provided by the DCE master Security and Naming replicas.
Planning Considerations
In your planning for HP Serviceguard, you must consider the following
characteristics of DCE and DCE-based programs:
• The DCE runtime and daemons do not themselves support the
concept of dynamic IP addresses.
• Normal DCE programming practice assumes that all IP addresses on
the host should be used for endpoints for exported services.
The DCE runtime determines the available IP addresses on the node
during the execution of any of the rpc_server_use_* routines. These
routines are used in every DCE server to select the protocols over which