Because the goal is to test the NFS tiebreaker function as a method for handling split-brain  situations, the additional local nodes in a linked multisite cluster are considered irrelevant and  not included in the test setup. Each node has its own cluster repository disk ( clnode_1r  and  clnode_2r ), and both nodes share a common cluster disk ( clnode_12 , which is the one that  must be protected from data corruption that is caused by a split-brain situation), as shown in  Example 3-13. clnode_1:/# lspv clnode_1r 00f6f5d0f8c9fbf4 caavg_private active clnode_12 00f6f5d0f8ca34ec datavg concurrent hdisk0 00f6f5d09570f170 rootvg active clnode_1:/# clnode_2:/# lspv clnode_2r 00f6f5d0f8ceed1a caavg_private active clnode_12 00f6f5d0f8ca34ec datavg concurrent hdisk0 00f6f5d09570f31b rootvg active clnode_2:/# Example 3-13 List of physical volumes on both cluster nodes To allow greater flexibility for our test scenarios, we chose to use different network adapters  for the production traffic and the connectivity to the shared NFS resource. The network setup  of the two nodes is shown in Example 3-14. Example 3-14 Network settings for both cluster nodes clnode_1:/# netstat -in | egrep "Name|en" Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll en0 1500 link#2 ee.af.e.90.ca.2 533916 0 566524 0 0 en0 1500 192.168.100 192.168.100.50 533916 0 566524 0 0 en0 1500 192.168.100 192.168.100.51 533916 0 566524 0 0 en1 1500 link#3 ee.af.e.90.ca.3 388778 0 457776 0 0 en1 1500 10 10.0.0.1 388778 0 457776 0 0 clnode_1:/# clnode_2:/# netstat -in | egrep "Name|en" Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll en0 1500 link#2 ee.af.7.e3.9a.2 391379 0 278953 0 0 en0 1500 192.168.100 192.168.100.52 391379 0 278953 0 0 en1 1500 link#3 ee.af.7.e3.9a.3 385787 0 350121 0 0 en1 1500 10 10.0.0.2 385787 0 350121 0 0 clnode_2:/# During the setup of the cluster, the NFS communication network with the  en1  network  adapters in Example 3-14 was discovered and automatically added to the cluster  configuration as a heartbeat network as  net_ether_02 . However, we manually removed it  afterward to prevent interference with the NFS tiebreaker tests. Therefore, the cluster  eventually had only one heartbeat network:  net_ether_01 . 70  IBM PowerHA SystemMirror V7.2.3 for IBM AIX and V7.2.2 for Linux