This tip gives some hints for enabling the FICON adapter in IBM eServer zSeries Linux so that it can load a tape device.

The Linux Fibre Channel adapter device driver zfcp.o is available in the kernel RPM package from your Linux distributor that supports the zSeries Fibre Channel Protocol. By default, zfcp.o is not loaded into the running kernel. There are three ways that you can load zfcp.o to see the tape devices on your system:

First, you need add the device map to this file. The following is an example of zfcp.conf:

0xf1c0 0x1:0x5005076300402733 0x0:0x0000000000000000;\

0xf1c1 0x1:0x5005076300402733 0x0:0x0001000000000000

The zfcp device driver uses the map module parameter to recognize a physically

attached tape device. The map takes the following format:

map="<devno><port scsi-id>:<wwpn><unit-scsi-lun>:<fcp-lun>;

Where:

0x0000000000000000 is the Logical Unit Number 0, and 0x0001000000000000 is the Logical Unit Number 1.

We recommend, for tape attachment, that each LUN be associated with a unique devno. If you use the same devno numbers for several logical units, you should ensure that each <unit-scsi-lun> is unique.

After /etc/zfcp.conf is created, run the following commands:

>mk_initrd

>zipl

Reboot the system. After it is booted up, your tape device should be shown in the /proc/scsi/scsi file.

You can add tape device mapping to the /etc/modules.conf file if you do not want to use the /etc/zfcp.conf file. The following example demonstrates the zfcp configuration in /etc/modules.conf:

options zfcp map="\

The map arguments are the same as the ones listed for the /etc/zfcp.conf file. After modifying /etc/modules.conf, save and close it. Then run the following commands:

This installs the zfcp device driver and all of its prerequisite kernel modules. Now, you can check the file /proc/scsi/scsi to see if all of the attached tape devices are shown in this file. If not, then check the Fibre Channel connection, such as the fiber cables, if the devices are powered on, and so on.  Then run the following commands to install zfcp:

>rmmod zfcp

>modprobe zfcp

If you physically attach a tape device on the switch, and zfcp is already loaded, you do not need to reboot the Linux system to add this entry in the /proc/scsi/scsi file. The zfcp device driver provides an add_map proc system entry under the directory /proc/scsi/zfcp to allow you to dynamically add the device into the system. For example, to add two LUNs from the above example into the system, you can issue the following commands:

>echo "0xf1c0 0x1:0x5005076300402733 0x0:0x0000000000000000;\

0xf1c1 0x1:0x5005076300402733

0x0:0x0001000000000000">/proc/scsi/zfcp/add_map

>echo "scsi add-single-device 0 0 10">/proc/scsi/scsi

>echo "scsi add-single-device 1 0 11">/proc/scsi/scsi

The “scsi add-single-device” takes four parameters, corresponding to the four parameters scsi, channel, id, and lun in the /proc/scsi/scsi file. The value of scsi is 0 for the first devno, 1 for the second devno (if it is different from the first devno), and so forth. The value of channel can start from 0 for each different SCSI value. The value of id is the one you use for <unit scsi-lun> in the above mapping. The value of lun is the LUN of the target device, for example, the last number in the above mapping.

Currently, the zfcp device driver does not support dynamically removing the attached devices. If you need to remove the tape devices from the system, do rmmod zfcp. Then, you can delete the entry in the /etc/modules.conf file and reload zfcp, or reload zfcp first and dynamically add the devices you want.