Here’s the cheet sheet to using native FC tools and drivers (tested on rhel5):

pWWN = cat /sys/class/fc_host/host[0-9]/port_name
WWN = cat /sys/class/fc_host/host[0-9]/node_name
online? = cat /sys/class/fc_host/host[0-9]/port_state
Speed = cat /sys/class/fc_host/host[0-9]/speed
HBA overview = cat /sys/class/fc_host/host[0-9]/symbolic_name
/sys/class/fc_host/host[0-9]/device/scsi_host\:host[0-9] is same as /sys/class/scsi_host/host[0-9]
HBA make = cat /sys/class/scsi_host/host[0-9]/model_desc
HBA model = cat /sys/class/scsi_host/host[0-9]/model_name
Firmware rev = cat /sys/class/scsi_host/host[0-9]/fw_version
Driver version = cat /sys/class/scsi_host/host[0-9]/driver_version
rescan scsi bus (use VERY wisely) = echo "- - -" > /sys/class/scsi_host/host[0-9]/scan
issue lip (use even MORE wisely) = echo 1 > /sys/class/fc_host/host[0-9]/issue_lip

It’s a good cheet sheet, but you’ll need more understanding to make this useful for your troubleshooting. Read on.

First, here is where the basic info is at:

ls -AF /sys/class/fc_host/host[0-9]
/sys/class/fc_host/host2:
device@ issue_lip port_id port_state speed subsystem@ supported_speeds system_hostname uevent
fabric_name node_name port_name port_type statistics/ supported_classes symbolic_name tgtid_bind_type

/sys/class/fc_host/host3:
device@ issue_lip port_id port_state speed subsystem@ supported_speeds system_hostname uevent
fabric_name node_name port_name port_type statistics/ supported_classes symbolic_name tgtid_bind_type

Notice: I did `ls -AF`, with which A=almost all (no . and ..) and F=classify, which adds *, /, =, >, @ or | to the end of the entries to describe what type of file it is. @ is a symlink and let me show you what one of those looks like.

lrwxrwxrwx 1 root root 0 Jul 2 16:44 device -> ../../../devices/pci0000:00/0000:00:09.0/0000:08:00.0/host3/

This is handy info – see how it matches this line from lspci {note that I’m just using one of the cards as a sample in the next two examples}.

lspci | grep 08:00
08:00.0 Fibre Channel: QLogic Corp. ISP2532-based 8Gb Fibre Channel to PCI Express HBA (rev 02)

Here’s a sample of the info you find in dmesg:

ACPI: PCI Interrupt 0000:08:00.0[A] -> GSI 32 (level, low) -> IRQ 51
qla2xxx 0000:08:00.0: Found an ISP2532, irq 51, iobase 0xffffc200100aa000
qla2xxx 0000:08:00.0: Configuring PCI space...
PCI: Setting latency timer of device 0000:08:00.0 to 64
qla2xxx 0000:08:00.0: Configure NVRAM parameters...
qla2xxx 0000:08:00.0: Verifying loaded RISC code...
qla2xxx 0000:08:00.0: Allocated (64 KB) for EFT...
qla2xxx 0000:08:00.0: Allocated (1414 KB) for firmware dump...
scsi3 : qla2xxx
qla2xxx 0000:0b:00.0: LIP reset occured (f7f7).
qla2xxx 0000:08:00.0:
QLogic Fibre Channel HBA Driver: 8.03.07.03.05.07-k
QLogic HPAK344A - HP 8Gb Single Channel PCI-e 2.0 FC HBA
ISP2532: PCIe (2.5Gb/s x8) @ 0000:08:00.0 hdma+, host#=3, fw=5.03.16 (95)
qla2xxx 0000:0b:00.0: LOOP UP detected (8 Gbps).
Vendor: SUN Model: ZFS Storage 7420 Rev: 1.0
Type: Direct-Access ANSI SCSI revision: 05

What if you want to find that model number or more about the current runing config? You can find that in both the fc_host directory and the scsi_host directory. Since we’re already in the fc_host tree, just follow the symlink.

ls -AF /sys/class/fc_host/host[0-9]/device/
/sys/class/fc_host/host2/device/:
ct edc edc_status els fc_host:host2@ fw_dump nvram optrom optrom_ctl power/ reset rport-2:0-0/ rport-2:0-1/ scsi_host:host2@ sfp uevent vpd

/sys/class/fc_host/host3/device/:
ct edc edc_status els fc_host:host3@ fw_dump nvram optrom optrom_ctl power/ reset rport-3:0-0/ rport-3:0-1/ scsi_host:host3@ sfp uevent vpd

See the “scsi_host” symlink? That’s a way to hop into where more of the info you need is at.

ls /sys/class/fc_host/host[0-9]/device/scsi_host\:host[0-9]/
/sys/class/fc_host/host2/device/scsi_host:host2/:
84xx_fw_version fabric_param isp_id mpi_version optrom_fw_version serial_num uevent vport_create
beacon flash_block_size isp_name npiv_vports_inuse pci_info sg_tablesize unchecked_isa_dma vport_delete
cmd_per_lun fw_state max_npiv_vports optrom_bios_version phy_version state unique_id zio
device fw_version model_desc optrom_efi_version proc_name subsystem vlan_id zio_timer
driver_version host_busy model_name optrom_fcode_version scan total_isp_aborts vn_port_mac_address

/sys/class/fc_host/host3/device/scsi_host:host3/:
84xx_fw_version fabric_param isp_id mpi_version optrom_fw_version serial_num uevent vport_create
beacon flash_block_size isp_name npiv_vports_inuse pci_info sg_tablesize unchecked_isa_dma vport_delete
cmd_per_lun fw_state max_npiv_vports optrom_bios_version phy_version state unique_id zio
device fw_version model_desc optrom_efi_version proc_name subsystem vlan_id zio_timer
driver_version host_busy model_name optrom_fcode_version scan total_isp_aborts vn_port_mac_address

With the above info, you should have enough to be able to accurately trackdown almost everything you need and make the cheet sheet above useful. Not everything is just a file (everything’s a file in unix). Some of those files are functions. How do you see changes to the FC fabric (such as when you update zoning)?

echo 1 > /sys/class/fc_host/host[0-9]/issue_lip

And here is what you do if you have the zones in place, but you have added luns that need to be seen.

echo "- - -" > /sys/class/scsi_host/host[0-9]/scan

I hope this is helpful for you. The next hurdle after this is using the native linux multipathing. I’ll add my cheet sheet for that sometime.