In HP 3PAR Storage arrays with more than two nodes, failover behavior occurs on node pairs; that is, if node 0 goes down, ports on node 0 fail over to node 1, if node 2 goes down, ports on node 2 fail over to node 3, and so on. Conversely, when node 1 goes down, ports on node 1 fail over to node 0, and when node 3 goes down, ports on node 3 fail over to node 2. When the downed node is up again, the
Persistent Ports Setup and Connectivity Guidelines
For Persistent Ports to function properly, specific cabling setup and connectivity guidelines that need to be followed can be found in the HP 3PAR Command Line Interface Administrator’s Manual, “Using Persistent Ports for Nondisruptive Online Software Upgrades.” See this document for other information about Persistent Ports as well.
The fabric switch ports connecting to the HP 3PAR array ports must support NPIV and have the feature enabled in order for Persistent Ports to work.
The showport command output includes Partner and FailoverState columns that display the partner port <node>:<slot>:<port> information and failover state information, respectively. FailoverState values represent the failover state of the two ports listed in the N:S:P and Partner columns. The FailoverState value can be one of the following:
•none: No failover in operation
•failover_pending: In the process of failing over to partner
•failed_over: Failed over to partner
•active: The partner port is failed over to this port
•active_down: The partner port is failed over to this port, but this port is down
•failback_pending: In the process of failing back from partner
Use the showport HP 3PAR CLI commands to get the state of the persistent ports. In the output of the showport command shown below, under the Partner column, port 1:1:1 is the partner port that 0:1:1 would fail over to and 0:1:1 is the partner port to which 1:1:1 would fail over. When Persistent Ports is not active, the FailoverState for the ports would indicate none.
#showport
N:S:P | Mode | State | - Port_WWN/HW_Addr- Type | Protocol Label | |||
Partner | Failover State |
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0:0:1 | initiator ready | 50002ACFF70185E1 | 50002ACFF70185E1 | disk | SAS | - | |
- | - |
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0:1:1 | target | ready | 2FF70002AC0185E1 | 2FF70002AC0185E1 | host | FC | - |
1:1:1 | none |
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When a node is down during an online upgrade or node reboot, from the output of the showport command, the FailoverState column would show that Persistent Ports is active. In the example below, node 1 has gone down, Persistent Ports for 1:1:1 has become active on port 0:1:1, and
all filesystem I/O for port 1:1:1 is physically served by port 0:1:1.
#showport
N:S:P | Mode | State | - Port_WWN/HW_Addr- Type | Protocol Label | |||
Partner | Failover State |
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0:0:1 | initiator ready | 50002ACFF70185E1 | 50002ACFF70185E1 | disk | SAS | - | |
- | - |
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0:1:1 | target | ready | 2FF70002AC0185E1 | 2FF70002AC0185E1 | host | FC | - |
1:1:1 | active |
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16 Configuring the HP 3PAR StoreServ Storage for Fibre Channel
