The msgmnb parameter specifies the maximum length of a message queue.
This parameter is specified in /var/sysgen/mtune/msg.
Value
Default: 32 * 1024 (0x8000)
Range: msgmax-1/2 of physical memory
When to Change
Increase this parameter if the maximum number of bytes on a message queue needs to be longer. Decrease the value to limit the number of bytes per message queue.