Queue manager configuration on the IBM MQ Appliance

Queue managers on the IBM® MQ Appliance are created with different default values to queue managers in IBM MQ.

Maximum channels

On the IBM MQ Appliance, you do not need to alter the MaxChannels or MaxActiveChannels attributes to define the maximum number of channels that can concurrently connect to a queue manager. On the IBM MQ Appliance, the default value of the MaxChannels and MaxActiveChannels attributes is set to infinite.

If you want to limit the maximum number of client channels, use the per-channel MAXINST and MAXINSTC attributes on the SVRCONN channel definitions to define limits for each SVRCONN channel:

MAXINST: Sets the maximum number of simultaneous instances of an individual SVRCONN channel that can be started.
MAXINSTC: Sets the maximum number of simultaneous individual SVRCONN channels that can be started from a single client. In this context, connections that originate from the same remote network address are regarded as coming from the same client.

You can use the DEFINE CHANNEL command to set these attributes. For more information, see DEFINE CHANNEL in the IBM MQ documentation.

TCP Network protocol

Any channels that are configured on an IBM MQ Appliance queue manager must be of TCP protocol type. The appliance does not support any other network protocols.

User and group permissions

IBM MQ Appliance queue managers support the user-based permissions model. Creating an authority record for a user results in only that user being granted access. To grant a group of users access, an authority record is required for the group.

Circular logging

IBM MQ Appliance queue managers support only circular logging. There is no support for creating a queue manager with linear logs.

Queue manager data

When you use the crtmqm command to create a queue manager on the appliance, a file system is created where all queue manager data, recovery logs, and errors logs are stored. The default size of this file system is 64 GB, but you can alter the size by using the -fs parameter with the crtmqm command.

Applications connecting to a queue manager

There are differences between applications that are connecting to a queue manager that is running on an IBM MQ Appliance, and one running in an IBM MQ installation. Queue managers that are running on the appliance support only applications that connect by using TCP, over IBM MQ channels.

Channel bind type

On the IBM MQ Appliance, channels connect to a queue manager by using FASTPATH binding. The default bind type on other platforms is to use STANDARD binding. FASTPATH binding is more efficient than STANDARD binding because channels run in the same process as the queue manager, instead of connecting by using inter-process communication. Although FASTPATH binding provides better performance it offers less isolation between a channel and the queue manager, so it should generally only be used in trusted environments. FASTPATH is the default bind type on the IBM MQ Appliance because it is a secure platform that does not permit user code, such as channel exits, to be configured that might compromise integrity.

If you want to change the bind type to STANDARD, then you can modify the MQIBindType attribute in the Channels stanza of a queue manager's qm.ini file, by using the setmqini command.

setmqini -m <qm-name> -s Channels -k MQIBindType -v STANDARD

To view the current channel settings in a queue manager's qm.ini file you can use the dspmqini command:

dspmqini -m <qm-name> -s Channels

For more information about the bind type, see Connecting to a queue manager using the MQCONNX call in the IBM MQ documentation. The full list of attributes that are supported for the Channels stanza in the qm.ini file are documented at Channels stanza of the qm.ini file.