HP 3PAR StoreServ 7200 2-node Administrator's Manual page 75

stay online and host multipath software is not affected. The online software upgrade completes
without any dependency on host multipath software.
Persistent ports can also be used to ensure nondisruptive host I/O activity for planned and unplanned
node down time, such as HBA firmware upgrades, adding or replacing HBAs, adding or replacing
DIMMs, node failures, and cable or switch failures.
NOTE: FC connections can support more than one partner port. iSCSI connections are limited
to one partner port due to the limitations of IP failover.
The following configuration requirements and limitations apply when using persistent ports for
port-level failover:
The host port must be connected and zoned through fabric topology to a HP 3PAR storage
system physical port.
The automatically-designated partner port must be connected to the same fabric as its partner
port on the same switch.
The partner port does not have to be zoned to the host port.
Under normal conditions, a host port has a single I/O path to the storage array available.
If a partner port is zoned to the same host port as the primary port, the host port has two I/O
paths to the storage array available.
The FC fabric used in the configuration must support NPIV.
Host-facing adapters on HP 3PAR storage systems used in the configuration must support NPIV.
FC adapters on hosts used in this configuration do not require NPIV support.
Port failover is only supported on target mode point to point port configurations.
Persistent port failover is only supported on the following NPIV-compliant HBAs:
HP 3PAR 4-port 4G FC
Emulex 2-port 4G
Emulex 4-port 8G FC
QLogic CNA in FCoE mode
QLogic 1G iSCSI
QLogic CNA in 10G iSCSI mode
Use the showport and showportdev commands to monitor the status of port failover and failback
operations.
The operating system assigns failover ports using a fixed mapping of N¹:S:P. N¹ uses the XOR
operator; therefore N¹ = N XOR 1. For example, port 0:1:1 partners with port 1:1:1. This means
that port 0:1:1 provides failover for 1:1:1 and port 1:1:1 provides failover for port 0:1:1.
The showport command output includes Partner and FailoverState columns that display
the partner port <node>:<slot>:<port> information and failover state information. 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.
Using Persistent Ports for Nondisruptive Online Software Upgrades 75