How to connect over Fibre Channel

How to connect to a target over Fibre Channel

Fibre Channel (FC) is one of the transports nvme connect supports. Addressing works differently from TCP and RDMA: there is no IP address, and you must give your own host's address explicitly.

This page is a worked example. For the general rules on --traddr and --host-traddr, see Using --host-traddr and --host-iface.

Requirements

• An FC host bus adapter (HBA) with a driver that supports FC-NVMe (for example lpfc or qla2xxx).
• The kernel's nvme_fc module.
• Fabric zoning that lets your host port see the target port. This is the same zoning an FC-SCSI setup needs; nvme-cli plays no part in it.

Addressing

Both --traddr (the target) and --host-traddr (your host) use the same format:

nn-<Node WWN>:pn-<Port WWN>

--host-traddr is mandatory for FC. There is no default, and --host-iface is not supported for FC.

Find your host port's address

Read the World Wide Node Name (WWNN) and World Wide Port Name (WWPN) from sysfs. Each local FC host adapter port has its own hostN entry:

$ cat /sys/class/fc_host/host0/node_name
0x200400110011cc22
$ cat /sys/class/fc_host/host0/port_name
0x200500110011cc22

These two values become your --host-traddr: nn-0x200400110011cc22:pn-0x200500110011cc22.

If more than one HBA port is present, check each /sys/class/fc_host/hostN/ in turn to find the one connected to your target's fabric.

Discover

nvme discover -t fc \
    -a nn-0x200400110011bb11:pn-0x200500110011bb11 \
    -w nn-0x200400110011cc22:pn-0x200500110011cc22

-a is the target's Discovery Controller address; -w is your host port from the previous step. An empty result usually means zoning, not nvme-cli -- confirm the target is visible to this host port first, with your FC switch's own tooling or the target's own configuration (for example nvmetcli).

Connect

nvme connect -t fc \
    -a nn-0x200400110011bb11:pn-0x200500110011bb11 \
    -w nn-0x200400110011cc22:pn-0x200500110011cc22 \
    -n nqn.2014-08.com.example:nvme.1

Persisting the connection

Add the same entry to nvme-fabrics.conf with nvme config create, so nvme connect-all reconnects it later:

nvme config create --transport fc \
    --traddr=nn-0x200400110011bb11:pn-0x200500110011bb11 \
    --host-traddr=nn-0x200400110011cc22:pn-0x200500110011cc22 \
    --hostnqn=nqn.2014-08.org.nvmexpress:uuid:62a4ab74-1e18-11f1-8bb7-6c1ff71ba506 \
    --discovery

See How to configure NVMe-oF connections for the full format.

Connecting automatically at boot

FC discovery events can trigger autoconnect on their own, without a config file. See the "Fibre Channel boot" section of How to set up NVMe-oF autoconnect.