11.1 SYS$PBDRIVER Port Devices When booting as both a Galaxy and as a cluster member, SYS$PBDRIVER will be loaded by default. The loading of this driver will create a device PBAx, where x represents the Galaxy partition Id. As other instances are booted, they will also create PBAx devices. The Shared Memory CI will quickly discover the other instances and create communi- cations channels to the other instances. Unlike traditional cluster interconnects, a new device will be created to com- municate to the other instances. This device will also have the name PBAx, where x represents the Galaxy partition Id for the instance with which this device is communicating. For example, look at a Galaxy consisting of two instances: MILKY and WAY. MILKY is instance 0 and WAY is in- stance 1. When node MILKY boots, it creates PBA0. When node WAY boots, it creates PBA1. As the two nodes discover each other, MILKY creates PBA1 to talk to WAY and WAY creates PBA0 to talk to MILKY. MILKY WAY PBA0: PBA1: PBA1: <-------> PBA0: 11.1.1 Multiple Clusters in a Single Galaxy SYS$PBDRIVER can support multiple clusters in the same Galaxy. This is done in the same way that SYS$PEDRIVER allows support for multiple clusters on the same LAN. The cluster group number and password used by SYS$PEDRIVER are also used by SYS$PBDRIVER to distinguish different clusters in the same Galaxy community. If your Galaxy in- stances are also clustered with other OpenVMS instances via the LAN, the cluster group number would be set appro- priately by CLUSTER_CONFIG. To determine the current cluster group number: $ MCR SYMAN SYSMAN> CONFIGURATION SHOW CLUSTER_AUTHORIZATION Node: MILKY Cluster group number: 0 Multicast address: xx-xx-xx-xx-xx-xx SYSMAN> If you are not clustering over a LAN and you want to run multiple clusters in the same Galaxy community, then you must set the cluster group number. You must insure that the group number and password is set the same for all Galaxy instances which you wish to be in the same cluster. $ MCR SYSMAN SYSMAN> CONFIGURATION SET CLUSTER_AUTHORIZATION/GROUP_NUMBER=222/PASSWORD=xxxx SYSMAN> In most cases, CLUSTER_CONFIG should do the right thing. If your Galaxy instances are also clustering over the LAN, CLUSTER_CONFIG will ask for a cluster group number and the Galaxy instances will utilize those group numbers. If you are not clustering over a LAN, the group number will default to zero. This means that all instances in the Galaxy will be in the same cluster.