Communicator e3000 MPE/iX Release 7.5 (Software Release C.75.00) (30216-90336)

Chapter 4
Fibre Channel Device and Adapter Support on HP e 3000 Systems
FCSCAN — Fibre Channel Device Scan Utility
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was run with hardware scan option, it actually probed the FC devices and recognized that the new device has
been connected. Thus by looking at this output, the System Administrator can get the hardware paths of
LUNs under N_Port 95 and use them to configure these disks in SYSGEN.
Note that now under card 0/8/0/0, the N_Port 0 is missing. It is possible that the device got disconnected.
Running FCSCAN with the “-h” option helps to view the current state of the FC devices and find out which
devices have been added to or removed from the system.
The “-h” option is particularly useful when the System Administrator wants to connect a new FC device to a
running system and configure the device online through IOCONFIG utility. After physically connecting the
device to the FC adapter card, the Administrator can run FCSCAN with “-h” option, find out the hardware
paths of the N_Ports/LUNs under this device and then use these hardware paths to configure them online
through IOCONFIG utility.
The output of FCSCAN with “-nh” option is the same as that of “-n” option, except that the list of N_Ports is
printed after an actual hardware scan is performed.
FCSCAN Output in Fabric Topology
A sample output of FCSCAN utility with the FC adapter card in fabric topology is shown below:
:fcscan
FCSCAN has found the following Fibre Channel I/O Adapter Cards and Devices on this system.
SYSGEN PATH DESCRIPTION BOOT MENU PATH
============= ============= ================
0/6/2/0 Fibre Channel Adapter
0/6/2/0.70383 Fibre Channel N-Port
0/6/2/0.70383.2 HP OPEN-3 disk 0/6/2/0.1.18.239.0.0.2
0/6/2/0.70383.12 HP OPEN-3 disk 0/6/2/0.1.18.239.0.1.4
0/6/2/0.70383.53 HP OPEN-3 disk 0/6/2/0.1.18.239.0.6.5
In the fabric topology output printed by FCSCAN, the path component corresponding to FC N_Port
represents the 24-bit N_Port ID. This path component value is usually a large number. But in the case of
private loop topology the value actually represents the Loop ID and is usually a smaller value. This detail is
being mentioned here just as a clarification for FCSCAN users. In spite of this, there is actually no difference
in the procedure for configuring the FC N_Port or devices in SYSGEN. For both topologies, the hardware path
value of the N_Port and devices as printed by FCSCAN can be used as such in SYSGEN for configuring them.
This implies that irrespective of the topology currently being used, the System Administrator can simply run
FCSCAN to determine the correct hardware paths and use the same for configuring in SYSGEN.
Fibre Channel Topology Changes
Whenever there is a topology change to the fibre channel standards, i.e., from private loop to public loop or
fabric to private loop, the addressing method for FC devices connected will change. This is because private
loop topology uses Loop ID based addressing while fabric and public loop topologies use N_port ID based
addressing. Since the Loop ID or the N_Port ID is present as a component in the hardware paths for FC
devices, a change in topology causes this hardware path to change. Since MPE/iX device addressing is based
on hardware paths configured in SYSGEN, a change in hardware path means that the device will no longer be
accessible using the original path. For this reason, it is not recommended to change the Fibre Channel
topology while the system is up and running.