HP Fibre Channel Mass Storage Adapters Support Guide FibrChanl-01 (fcd) Driver

• AH401A
• 403619-B21
• AD193A
• AD194A
• AD300A
• AB378B
• AB379B
• AB378A
• AB379A
• A6826A
• A9782A
• A9784A
• AB465A
For more information on this command, see the fcmsutil (1M) manpage.
When the fcd driver discovers a new target device, it creates a hardware path for that device
based on the N_Port ID. The N_Port ID is the Fibre Channel address for a device, and a way of
identifying the device in a Storage Area Network (SAN). The fcd driver will also associate a
device’s World Wide Name (WWN) with its N_Port ID.
Each time the fcd driver opens a target device at an N_Port ID, it compares the WWN for the
target device to the WWN of the driver associated with the N_Port ID for that device, when the
device was discovered. If the WWNs are not the same, the fcd driver logs an error message and
does not allow access to that device. This prevents data corruption if a target device is connected
through an N_Port ID that belongs to a different target device; for example, if two JBODs are
plugged into each other’s switch ports by mistake.
If you want to intentionally replace a target device, for example a bad disk, use the fcmsutil
<device_file> replace_dsk <remote-N-Port-ID> command to force the fcd driver to
recognize a new target device at an N_Port ID that was previously used by a different target
device. The replace_dsk command replaces the device WWN that is currently associated with
a particular N_Port ID with the WWN of the device that is actually connected through that N_Port
ID at the time the replace_dsk command is executed.
The association between a target device WWN and an N_Port ID persists until the system is
rebooted, or the fcmsutil <device_file> replace_dsk <remote-N-Port-ID> command
is executed for that N_Port ID.
Device Replacement without System Reboot using scsimgr (HP-UX 11.31
only)
The scsimgr replace_wwid command described in this section enables target device
replacement without a system reboot on HP-UX 11i v3 systems.
Device Replacement without System Reboot using scsimgr (HP-UX 11.31 only) 19