Maximum instances per client (MAXINSTC)

This attribute can be set from zero through 999 999 999. A value of zero indicates that no client connections are allowed on this channel. The default value is 999 999 999.

The Client Attachment feature (CAF) is an option of WebSphere® MQ for z/OS that supports the attachment of clients to z/OS. If you do not have the Client Attachment feature (CAF) installed, the attribute can be set from zero to five only on the SYSTEM.ADMIN.SVRCONN channel. A value greater than five is interpreted as zero without the CAF installed.

If the value is reduced below the number of instances of the server-connection channel that are currently running from individual clients, then the running channels are not affected. However, new instances from those clients are not able to start until sufficient existing ones have ceased to run.

This attribute is valid for server-connection channels only.