WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

14.5.4 XCF—alternative protocol on z/OS
This section describes how the XCF system service is used to enhance the
WebSphere Application Server for z/OS V7.0 DCS protocol.
WebSphere Application Server for z/OS architectural change
From an architectural side, the usage of XCF adds some components to a
WebSphere environment, as shown in Figure 14-8.
Default HA Manager
Distribution and
Consistency Service
Failure
Detection
Discovery
Service
Alternative
protocol
Figure 14-8 Architectural changes when using XCF support
As seen in Figure 14-8, the main changes are:
► The internal failure detection of the HA manager will be factored out of the
DCS structure. Instead, XCF’s failure detection will be used to notify the HA
manager.
► The Discovery Service, used to communicate with the HA manager now talks
to the XCF component of z/OS.
► XCF plugs into DCS to perform the alive check. This will disable the TCP/IP
ping-based heartbeat.
If a member can no longer be contacted, the protocol will notify the core group
members and issue message DCSV1032I in the SystemOut.log file.
442 WebSphere Application Server V7.0: Concepts, Planning, and Design
HA Manager with XCF
Distribution and
Consistency Service
Failure
Detection
XCF Plug-In
XCF
Discovery
Service