In openFT you can run multiple openFT instances on one computer simultaneously. Because of these instances, should a computer fail, you are in a position to carry over the functionality of the openFT to another computer, which is already running openFT.
After installing openFT, the standard instance exists on each computer. This instance is atypical in that it cannot be deleted by instance management commands. Its application data is located on the default pubset under ID $SYSFJAM. When instances are displayed (SHOW-FT-INSTANCE), the standard instance is always displayed first.
Up to 16 additional instances can be created by administration. Each of these instances, including the standard instance, consists of the following components:
The request file SYSRQF, the partner list SYSPTF, the logging file SYSLOG, trace files, options SYSOPF and the profile file SYSFSA.
Each instance therefore requires a configuration user ID with the characteristics that are described for the SYSFJAM ID (see section “Preparing the FT system”).Exception: It is not necessary that the configuration user ID is located on the home pubset.Each instance requires its own network address; this always remains the same, independent of the real host.
The host name must therefore be stored in the options using the MODIFY-FT-OPTIONS command. This (virtual) BCAM host must always be accessible under the same network address. In order to prevent the BCAM connection setup from automatically being passed to the real host instance when an instance fails to start, BCAM aliasing should be disabled for the $FJAM and $FTAM applications.
The openFT installation files are only available once per computer and are shared by all the instances. The same version, however, must be installed on all the computers in the cluster (openFT version, release version, reps, etc.).
openFT commands that are called during a preprocessing, postprocessing or follow-up processing session, run under the same instance as the request that initiated the processing.