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Chapter 12. Configuring Fibre Channel over Ethernet

Based on the IEEE T11 FC-BB-5 standard, Fibre Channel over Ethernet (FCoE) is a protocol to transmit Fibre Channel frames over Ethernet networks. Typically, data centers have a dedicated LAN and Storage Area Network (SAN) that are separated from each other with their own specific configuration. FCoE combines these networks into a single and converged network structure. Benefits of FCoE are, for example, lower hardware and energy costs.

12.1. Using hardware FCoE HBAs in RHEL

In RHEL you can use hardware Fibre Channel over Ethernet (FCoE) Host Bus Adapter (HBA), which is supported by the following drivers:

  • qedf
  • bnx2fc
  • fnic

If you use such a HBA, you configure the FCoE settings in the setup of the HBA. For more information, see the documentation of the adapter.

After you configure the HBA, the exported Logical Unit Numbers (LUN) from the Storage Area Network (SAN) are automatically available to RHEL as /dev/sd* devices. You can use these devices similar to local storage devices.

12.2. Setting up a software FCoE device

Use the software FCoE device to access Logical Unit Numbers (LUN) over FCoE, which uses using an Ethernet adapter that partially supports FCoE offload.

Important

RHEL does not support software FCoE devices that require the fcoe.ko kernel module.

After you complete this procedure, the exported LUNs from the Storage Area Network (SAN) are automatically available to RHEL as /dev/sd* devices. You can use these devices in a similar way to local storage devices.

Prerequisites

  • You have configured the network switch to support VLAN.
  • The SAN uses a VLAN to separate the storage traffic from normal Ethernet traffic.
  • You have configured the HBA of the server in its BIOS.
  • The HBA is connected to the network and the link is up. For more information, see the documentation of your HBA.

Procedure

  1. Install the fcoe-utils package:

    # yum install fcoe-utils
  2. Copy the /etc/fcoe/cfg-ethx template file to /etc/fcoe/cfg-interface_name. For example, if you want to configure the enp1s0 interface to use FCoE, enter the following command:

    # cp /etc/fcoe/cfg-ethx /etc/fcoe/cfg-enp1s0
  3. Enable and start the fcoe service:

    # systemctl enable --now fcoe
  4. Discover the FCoE VLAN on interface enp1s0, create a network device for the discovered VLAN, and start the initiator:

    # fipvlan -s -c enp1s0
    Created VLAN device enp1s0.200
    Starting FCoE on interface enp1s0.200
    Fibre Channel Forwarders Discovered
    interface       | VLAN | FCF MAC
    ------------------------------------------
    enp1s0          | 200  | 00:53:00:a7:e7:1b
  5. Optional: Display details about the discovered targets, the LUNs, and the devices associated with the LUNs:

    # fcoeadm -t
    Interface:        enp1s0.200
    Roles:            FCP Target
    Node Name:        0x500a0980824acd15
    Port Name:        0x500a0982824acd15
    Target ID:        0
    MaxFrameSize:     2048 bytes
    OS Device Name:   rport-11:0-1
    FC-ID (Port ID):  0xba00a0
    State:            Online
    
    LUN ID  Device Name   Capacity   Block Size  Description
    ------  -----------  ----------  ----------  ---------------------
         0  sdb           28.38 GiB      512     NETAPP LUN (rev 820a)
         ...

    This example shows that LUN 0 from the SAN has been attached to the host as the /dev/sdb device.

Verification

  • Display information about all active FCoE interfaces:

    # fcoeadm -i
    Description:      BCM57840 NetXtreme II 10 Gigabit Ethernet
    Revision:         11
    Manufacturer:     Broadcom Inc. and subsidiaries
    Serial Number:    000AG703A9B7
    
    Driver:           bnx2x Unknown
    Number of Ports:  1
    
        Symbolic Name:     bnx2fc (QLogic BCM57840) v2.12.13 over enp1s0.200
        OS Device Name:    host11
        Node Name:         0x2000000af70ae935
        Port Name:         0x2001000af70ae935
        Fabric Name:       0x20c8002a6aa7e701
        Speed:             10 Gbit
        Supported Speed:   1 Gbit, 10 Gbit
        MaxFrameSize:      2048 bytes
        FC-ID (Port ID):   0xba02c0
        State:             Online

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