Question & Answer
What combinations of JCC's Sysplex, Client Reroute and Connection Concentrator features are supported when going through DB2 Connect LUW to DB2 on Z/OS server.
In addition to using JDBC APIs, the IBM Data Server Driver for JDBC and SQLJ (JCC ) is capable of load balancing by using Sysplex routing, connecting to other nodes after failure (Automatic Client Reroute), and connecting more than one application through the same connection (Connection Concentrator). DB2 Connect is also capable of using Sysplex load balancing, client reroute and connection concentration, consequently when the JCC driver is connecting to a Z/OS through DB2 Connect LUW (Linux, Unix, Windows) certain combinations of JCC Sysplex enablement, Automatic Client Reroute and Connection Concentrator are not supported.
Unsupported Usage of the JCC Sysplex Feature for DB2 on Z/OS.
The JCC driver does not support going to a Sysplex enabled Z/OS DB2 through a DB2 Connect Server with the enableSysplexWLB property set to true as this activates the JCC driver's Sysplex feature. Since the DB2 Connect gateway also has a Sysplex feature the results can be unpredictable.
Supported Usage of the JCC Sysplex Feature for DB2 on Z/OS.
It is supported to go to a Sysplex enabled DB2 Z/OS through a DB2 Connect server using type 4 mode if the enableSysplexWLB property is set to false. It is also supported to go to a Sysplex enabled DB2 Z/OS through a DB2 Connect server using type 2 mode. The enableSysplexWLB property only applies to applications using type 4 mode and is ignored when the application is using type 2 mode. The JCC driver also supports connecting to a DB2 Z/OS that does not have Sysplex enabled, in both type 4 and type 2 modes. Going directly to a Sysplex enabled DB2 Z/OS from a JCC application in type 4 mode (without passing through a DB2 Connect Server) with the enableSysplexWLB property set to true is also supported.
Supported Usage of JCC Client Reroute.
JCC Client Reroute is supported when connecting to a Sysplex enabled Z/OS DB2 server providing that the reroute is setup to occur between DB2 LUW servers (DB2 Connect is also considered a LUW server) and enableSysplexWLB is set to false. Automatic client reroute will occur between LUW servers when an Alternate Server entry is present in the server catalogs. Once client reroute is setup, if connectivity to the application running JCC fails, the JCC driver will reroute the connection to the alternate LUW server but not to an alternate DB2 for Z/OS Sysplex member. If the connection between the LUW Server and the DB2 for Z/OS fails the LUW server will reroute the connection to an alternate Sysplex member.
Unsupported Usage of the JCC Connection Concentrator.
Using the JCC Connection Concentrator (by setting the enableConnectionConcentrator property to true) to reach the DB2 Connect gateway is not supported. The DB2 Connect gateway has its own Connection Concentrator that can be used to concentrate the connections between the DB2 Connect server and DB2 on Z/OS.
Supported Usage of the JCC Connection Concentrator.
Connecting directly to a Z/OS DB2 from a JCC application in type 4 mode with the Connection Concentrator enabled (the enableConnectionConcentrator property is set to true) is supported.
16 June 2018