When installing Shareplex, the normal sequence of event is to set up the environment variables for SP_SYS_VARDIR, SP_COP_UPORT, SP_COP_TPORT, ORACLE_SID, ORACLE_HOME, etc, and then run the .tpm file for the Shareplex patch in question (for version 6.0 and up) or run the .run file for the Shareplex base install and the Shareplex patch respectively. In general, the Oracle is already up and running prior to running the install file. The question arises as to whether it is possible to run the installation file if the Oracle database in question is not yet installed or available?
It is not possible to do installation/upgrade of Shareplex without having Oracle installed. It is true that the Oracle need not be up or running during that period.
For Shareplex version 5.3 or lower Shareplex creates a soft link from /var/adm/.splex/V-<shareplex version>/lib<oracle version> to $ORACLE_HOME/lib32 directory. If the Oracle is not installed on that location yet, then the Shareplex installation/upgrade will error out. The upgrade process also checks for existence of the values for ORACLE_HOME and ORACLE_SID as provided by the environment variables by referencing the oratab file. If they do not exist, then it may error out as well. Further, Oracle needs to be running when later the ora_setup has to be run.
For Shareplex version 6.0 and up, there is no role of the directory /var/adm/.splex/V-<shareplex version>/lib<oracle version> but the existence of ORACLE_HOME, ORACLE_SID, and LD_LIBRARY_PATH are required.
These types of questions come up when users want to carry out activities in parallel during maintenance windows to reduce downtime. But certain activities depend on other activities to finish before they can be started. This holds true for Oracle install and Shareplex install in that order.