25.2. Adding FCP-Attached Logical Units (LUNs)

The following is an example of how to add an FCP LUN.

Note

If running under z/VM, make sure the FCP adapter is attached to the z/VM guest virtual machine. For multipathing in production environments there would be at least two FCP devices on two different physical adapters (CHPIDs). For example:

CP ATTACH FC00 TO * 
CP ATTACH FCD0 TO *

25.2.1. Dynamically activating an FCP LUN

Follow these steps to activate a LUN:

Use the cio_ignore command to remove the FCP adapter from the list of ignored devices and make it visible to Linux:
```
# cio_ignore -r device_number
```
Replace device_number with the device number of the FCP adapter. For example:
To bring the FCP adapter device online, use the following command:
```
# chccwdev -e fc00
```

Verify that the required WWPN was found by the automatic port scanning of the zfcp device driver:

# ls -l /sys/bus/ccw/drivers/zfcp/0.0.fc00/
drwxr-xr-x.  3 root root    0 Apr 28 18:19 0x500507630040710b
drwxr-xr-x.  3 root root    0 Apr 28 18:19 0x50050763050b073d
drwxr-xr-x.  3 root root    0 Apr 28 18:19 0x500507630e060521
drwxr-xr-x.  3 root root    0 Apr 28 18:19 0x500507630e860521
-r--r--r--.  1 root root 4096 Apr 28 18:17 availability
-r--r--r--.  1 root root 4096 Apr 28 18:19 card_version
-rw-r--r--.  1 root root 4096 Apr 28 18:17 cmb_enable
-r--r--r--.  1 root root 4096 Apr 28 18:17 cutype
-r--r--r--.  1 root root 4096 Apr 28 18:17 devtype
lrwxrwxrwx.  1 root root    0 Apr 28 18:17 driver ->  ../../../../bus/ccw/drivers/zfcp
-rw-r--r--.  1 root root 4096 Apr 28 18:17 failed
-r--r--r--.  1 root root 4096 Apr 28 18:19 hardware_version
drwxr-xr-x. 35 root root    0 Apr 28 18:17 host0
-r--r--r--.  1 root root 4096 Apr 28 18:17 in_recovery
-r--r--r--.  1 root root 4096 Apr 28 18:19 lic_version
-r--r--r--.  1 root root 4096 Apr 28 18:17 modalias
-rw-r--r--.  1 root root 4096 Apr 28 18:17 online
-r--r--r--.  1 root root 4096 Apr 28 18:19 peer_d_id
-r--r--r--.  1 root root 4096 Apr 28 18:19 peer_wwnn
-r--r--r--.  1 root root 4096 Apr 28 18:19 peer_wwpn
--w-------.  1 root root 4096 Apr 28 18:19 port_remove
--w-------.  1 root root 4096 Apr 28 18:19 port_rescan
drwxr-xr-x.  2 root root    0 Apr 28 18:19 power
-r--r--r--.  1 root root 4096 Apr 28 18:19 status
lrwxrwxrwx.  1 root root    0 Apr 28 18:17 subsystem ->  ../../../../bus/ccw
-rw-r--r--.  1 root root 4096 Apr 28 18:17 uevent

Activate the FCP LUN by adding it to the port (WWPN) through which you would like to access the LUN:
```
# echo 0x4020400100000000 > /sys/bus/ccw/drivers/zfcp/0.0.fc00/0x50050763050b073d/unit_add
```

Find out the assigned SCSI device name:

# lszfcp -DV
/sys/devices/css0/0.0.0015/0.0.fc00/0x50050763050b073d/0x4020400100000000
/sys/bus/ccw/drivers/zfcp/0.0.fc00/host0/rport-0:0-21/target0:0:21/0:0:21:1089355792

For more information, refer to the chapter on SCSI-over-Fibre Channel in Linux on System z Device Drivers, Features, and Commands on Red Hat Enterprise Linux 6.