Using Multi-instance mode and automatic client reconnect features of WMQ with TXSeries
Arpana Kulenur 310001AVMY Visits (2731)
Multi-instance queue managers are instances of the same queue manager configured on two or more computers. By starting multiple instances, one instance becomes the active instance and the other instances become standbys. If the active instance fails, a standby instance running on a different computer automatically takes over. The channels are defined with multiple connection names, hence when the client detects a connection failure it automatically reconnects to the newly active queue manager instance, hence providing high availability.
Check WMQ infocenter for configuration and more details on Multi-instance qmgr.
To exploit the above high availability feature of WMQ with TXSeries, we need to use MQCHLTAB and MQCHLLIB environment variables provided by WMQ to specify channel details and only provide the qmgr name in xa_open attribute in XAD stanza of TXSeries region. Also we need to define the network addresses in channel definitions to all instances of multi-instance queue manager.
Steps to configure:
· Define wmq channel for communication between WMQ client and server.
· The client channel definition table(CCDT) file is created on wmq server machine and needs to copied to the MQ client machine. The CCDT determines the channel definitions used by client applications to connect to the queue manager.
· Set MQCHLTAB and MQCHLLIB environment variables as shown below.
export MQCHLTAB= AMQCLCHL.TAB
MQCHLTAB specifies the name of the file containing the client channel definition table.
MQCHLLIB specifies the directory path to the file containing the client channel definition table.