Karl R. Balsmeier wrote: > How does one configure a fence device in the form of a NIC card in > centos 5? Is the gnbd item relevant to this? I'm not sure what 'a fence device in the form of a NIC card' is. the fence devices I'm familiar with include SCSI fence switches, fiberchannel SAN switches, and APC SmartPlug power switches. in my test cluster, I used a Qlogic SANbox fiber switch to connect the cluster nodes to the shared storage. the fencing was done by sending the Qlogic the commands to enable/disable the ports of the two nodes so only the active node could access the shared storage. I suppose an Ethernet analog in an ISCSI SAN environment would be to send commands to a layer-2 or layer-3 managed switch to manipulate the VLANs to disable the standby nodes from accessing the ISCSI target device. These systems would need separate dedicated NICs for LAN connectivity and cluster heartbeats.