Setting up the zfcp device driver

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SUSE Linux™ Enterprise Server 12 SP4 loads the zfcp device driver for you when an FCP channel becomes available. Use YaST to configure the zfcp device driver.

You have the following options for configuring FCP:
  • Use the YaST GUI yast2 zfcp. If cio_ignore is enabled, you might need to free blacklisted FCP devices beforehand by using yast2 cio.
  • Use the text-based interface yast zfcp. If cio_ignore is enabled, you might need to free blacklisted FCP devices beforehand by using yast cio
  • Use the command line, use zfcp_host_configure. It transparently frees the FCP device specified on the command line from cio_ignore. cio_ignore does not apply to zfcp_disk_configure.
See the section about hard disk configuration in the SUSE Linux Enterprise Server 12 SP4 Deployment Guide, and the procedure about configuring a zFCP disk in SUSE Linux Enterprise Server 12 SP4 Administration Guide. The command-line tools described work not only inside the rescue environment but also in a regularly installed Linux instance.
Important: Configuration changes can directly or indirectly affect information that is required to mount the root file system. Such changes require an update of the initrd of both the auxiliary kernel and the target kernel, followed by a re-write of the boot record (see Rebuilding the initial RAM disk image).

The parameters are described in the context of the modprobe command. For details about specifying kernel and module parameters, see Kernel and module parameters.

Figure 1. zfcp module parameter syntax

1  modprobe zfcp
1!  allow_lun_scan=1
1?  allow_lun_scan=<value>
1!  datarouter=1
1?  datarouter=0
1!  dbflevel=3
1?  dbflevel=<level>
1!  dbfsize=4
1?  dbfsize=<pages>
1!  dif=0
1?  dif=<value>
1!  port_scan_ratelimit=60000
1?  port_scan_ratelimit=<limit>
1!  port_scan_backoff=500
1?  port_scan_backoff=<delay>
1!  no_auto_port_rescan=0
1?  no_auto_port_rescan=1
1!  queue_depth=32
1?  queue_depth=<depth>
where:
allow_lun_scan=<value>
disables the automatic LUN scan for FCP devices that run in NPIV mode if set to 0, n, or N. To enable the LUN scanning set the parameter to 1, y, or Y. When the LUN scan is disabled, all LUNs must be configured through the unit_add zfcp attribute in sysfs. LUN scan is enabled by default.
datarouter=
enables (if set to 1, y, or Y) or disables (if set to 0, n, or N) support for the hardware data routing feature. The default is 1.
Note: The hardware data routing feature becomes active only for FCP devices that are based on adapter hardware with hardware data routing support.
dbflevel=<level>
sets the initial log level of the debug feature. The value is an integer in the range 0 - 6, where greater numbers generate more detailed information. The default is 3.
dbfsize=<pages>
specifies the number of pages to be used for the debug feature.

The debug feature is available for each FCP device and the following areas:

hba
FCP device
san
Storage Area Network
rec
Error Recovery Process
scsi
SCSI
pay
Payloads for entries in the hba, san, rec, or scsi areas. The default is 8 pages.
The value that is given is used for all areas. The default for hba, san, rec, and scsi is 4, that is, four pages are used for each area and FCP device. In the following example the dbsfsize is increased to 6 pages: 
zfcp.dbfsize=6
This results in six pages being used for each area and FCP device. The payload is doubled to use 12 pages.
dif=<value>
turns on end-to-end data consistency checking if set to 1, y, or Y and off if set to 0, n, or N. The default is 0.
port_scan_ratelimit=<limit>
sets the minimum delay, in milliseconds, between automatic port scans of your Linux instance. The default value is 60000 milliseconds. To turn off the rate limit, specify 0. Use this parameter to avoid frequent scans, while you still ensure that a scan is conducted eventually.
port_scan_backoff=<delay>
sets additional random delay, in milliseconds, in which the port scans of your Linux instance are spread. The default value is 500 milliseconds. To turn off the random delay, specify 0. In an installation with multiple Linux instances, use this attribute for every Linux instance to spread scans to avoid potential multiple simultaneous scans.
no_auto_port_rescan=
turns the automatic port rescan feature off ( if set to 1, y, or Y) or on (if set to 0, n, or N). The default is 0. Automatic rescan is always run when an adapter is set online and when user-triggered writes to the sysfs attribute port_rescan occur.
queue_depth=<depth>
specifies the number of commands that can be issued simultaneously to a SCSI device. The default is 32. The value that you set here is used as the default queue depth for new SCSI devices. You can change the queue depth for each SCSI device with the queue_depth sysfs attribute.
device=<device_bus_id>, <wwpn>, <fcp_lun>
Attention: The device= module parameter is reserved for internal use. Do not use.
<device_bus_id>
specifies the FCP device through which the SCSI device is attached.
<wwpn>
specifies the target port through which the SCSI device is attached.
<fcp_lun>
specifies the LUN of the SCSI device.