A file server stores the project files associated with a PDS project. This includes seed files, reference libraries, report format files, the actual 2D and 3D model files, and many other associated support files. By storing all such files on a dedicated server, backups are made easier and centralized access control can be established. A file server should have a large amount of disk space, a tape backup device, and a high-speed networking subsystem.
A database server stores the RDBMS used by the PDS software. Its requirements are similar to those of the file server. Many users choose to use a single machine as the file and database server for small-to-medium sized projects.
Intergraph recommends that, for optimal performance, client machines be provided with sufficient disk space such that all frequently used applications can be loaded locally. However, infrequently used applications can be loaded in client mode. In this configuration, the client machine mounts a disk from the software server and runs the software over the network. This can place a significant load on the network, so it is not suggested for heavily used applications.
When a large number of jobs are being run that consume significant amounts of CPU time (hidden line removal, large reports, isometric extractions, clash detection, and so on), it can be advantageous to set up a compute server. In this configuration, the client workstations reconfigure their local batch queues to be pipe queues that point to the compute server. When batch jobs are submitted by the clients, they are redirected to the compute server, which performs the calculations and returns output to the client.
Depending on the number of plotting devices in use, the number of plots being produced, and the size and type of the plots, it can be advantageous to set up a plot server. This machine has all I/O cards required to interface with the plotting devices, all server plotting software, and sufficient memory to cache certain kinds of plots (typically large raster plots).
PDS License Server
When you purchase or lease PDS, you are provided a key that provides you with a number of PDS licenses. Licenses are graded by functionality---3D, 2D, PID, and IDM. A PDS key contains encoded information that tells the system how many of each kind of license you have and when they expire. SmartPlant License Manager distributes these licenses as requested by the clients. It keeps track of how many licenses of which type have been given out and how many remain in the pool. If all licenses of a particular type are checked out, a new interactive request will fail immediately while a batch job will be placed into a wait state.
Acting as a PDS license server places very little load on the selected node---its choice should be based on it having a stable TCP/IP address (keys are installable only on a node having a specific address) and its accessibility to the system administrator.
PDS is flexible in that these servers can be configured and decommissioned during the course of a single project. Not all functions require a separate server in all circumstances. Multiple server functions can be consolidated on a single machine. Specific recommendations as to what functions need to be relocated to separate servers is beyond the scope of this book. It is to your advantage to have a knowledgeable system administrator on staff who can monitor overall system performance and identify trends in system usage that will point out when a particular server is reaching the limits of its resources.