As indicated in the previous section, the [RPCMANAGER-SERVERS] section of the Config.ini configuration file lists the primary and backup RPC Manager/configuration servers for your application. By default, it is the RPC Manager primary and backup server configuration that ultimately controls all VTS services; however, it is possible to modify your application's configuration in such a way that each individual service uses its own independent roster of primary and backup servers so that the workload is spread across several different workstations, rather than overtaxing one workstation with the management of all services. This configuration of separate servers for separate services also helps to prevent unnecessary down time in the event that the primary RPC Manager server should fail and must go through synchronization with the next backup server on its list.
To configure separate servers for separate services, you must create new section headings in your Config.ini configuration file, each featuring the name of a service followed by "–Servers", beneath which you can specify the names (or IPs) of the primary and backup servers for the service. An example is displayed below:
[LOGMANAGER-SERVERS]
Name = FREDSPC
Name = JOANSPC
As you can see in the above example, two PCs have been configured as the primary and backup servers for the Log Manager. (The LogManager allows only one backup. Other services may allow more. )
During normal operations, the Log Manager's primary server will be FREDSPC; however, if FREDSPC were to fail or become unavailable, the next server in the list (in our example, "JOANSPC") would take over the responsibilities of primary Log Manager server until such a time as FREDSPC resumes operations.
Note: You should always use workstation names other than IP addresses when you are specifying configuration servers or service servers, especially in networks where the workstations may be dual-homed, or where dynamic IPs are assigned. This will help to avoid any miscommunication that could occur in the event that an IP is reassigned to a third workstation while transmissions between two workstations is in progress.
For many services, backup servers behave the same as the primary server when they are called upon to assume that role; however, there is one service for which the fail-over procedure differs.
For the Edit Lockout Manager service, the designated primary server is required to perform online configuration actions. If only a backup ELM server is available, only operational changes may be performed on the application. If no server is available (neither the primary ELM server nor a backup ELM server), operational changes may still be performed on the local workstation, but they will not be propagated to the other workstations on the network until a connection with a server is established.
It should be noted that if one workstation has a tag locked, and another workstation does an operational change, the operational change will still be applied to the tag's properties, even if that particular property has already been edited by the lock-holder.
If you require further information on primary configuration servers and backup servers, server redundancy, or networked VTS applications, please refer to "VTS Developer's Guide: Introduction to Remote Applications".
The following sections pertain to the different VTS services for which you may specify different servers:
[RPCMANAGER-SERVERS]
[LOGMANAGER-SERVERS]
[ALARMMANAGER-SERVERS]
[SECURITYMANAGER-SERVERS]
[EDITLOCKOUTMANAGER-SERVERS]