CARMA and stack affinity

CARMA (Common Access Repository Manager) is used to access a host-based Software Configuration Manager (SCM), for example CA Endevor® SCM. To do so, CARMA starts a user-specific server, which needs additional configuration to enforce stack affinity.

Similar to the z/OS® Explorer started tasks, stack affinity for a CARMA server is set with the _BPXK_SETIBMOPT_TRANSPORT variable, which must be passed on to LE (Language Environment®). This can be done by adjusting the startup command in the active crastart*.conf or CRASUB* configuration file.

Note:
  • The exact name of the configuration file that holds the startup command depends on various choices made by the systems programmer who configured CARMA. Refer to "Chapter 3. (Optional) Common Access Repository Manager (CARMA)" in the Host Configuration Guide (SC27-9933) for more information about this.
  • _BPXK_SETIBMOPT_TRANSPORT specifies the name of the TCP/IP stack to be used, as defined in the TCPIPJOBNAME statement in the related TCPIP.DATA.
  • Coding a SYSTCPD DD statement does not set the requested stack affinity.
  • By default, CARMA does not use the normal TCP/IP stacks. CARMA uses the loopback address for the communication between CARMA miner and CARMA server. This improves security (only local processes have access to the loopback address) and is likely to prevent the need to add stack affinity to CARMA communication.