Dual-mode FC configuration
Enabling FC target mode on QuantaStor means dual mode -- initiator and target at the same time, rather than target alone. Both roles are needed: the target role presents LUNs to FC hosts, and the initiator role is what lets the appliance enumerate the FC initiators visible on the fabric. Without it the appliance is invisible to its own fabric, so target mode and dual mode go together.
The mode is set by the qlini_mode option on the QLogic driver, applies to the whole appliance rather than to an individual port, and takes effect at boot. Use the qs-util verbs below rather than editing the driver configuration by hand -- they write the correct values to the file the product expects.
| Mode | qlini_mode |
What it gives you |
|---|---|---|
| Dual (use this for FC target) | dual |
Initiator and target together. FC target ports serve LUNs, and FC remote ports on the fabric are discoverable. |
| Target only | exclusive |
Target only. LUNs are served, but no FC initiators are discoverable -- see the warning below. |
Checking the current mode
The Mode column reports each port's active mode. From the appliance, read it per port from sysfs -- substitute your own hostN, which you can list with ls /sys/class/fc_host/:
cat /sys/class/fc_host/host7/device/scsi_host/host7/active_mode
Dual mode prints both roles:
Initiator, Target
To see the value the driver was actually loaded with:
cat /sys/module/qla2xxx_scst/parameters/qlini_mode
Setting dual initiator + target mode
sudo qs-util enabledualmode sudo reboot
This writes qlini_mode=dual to /etc/modprobe.d/qla2xxx.conf for both the qla2xxx and qla2xxx_scst module names. A reboot is required -- the option is read when the driver loads.
After the reboot, confirm both roles are present with the active_mode check above.
Setting target-only mode
sudo qs-util disabledualmode sudo reboot
This writes qlini_mode=exclusive, and the ports come up in target mode without transitioning from initiator mode at boot.
Target-only mode makes FC initiators invisible to the appliance. With exclusive set, qs fc-remote-port-list returns nothing and the Select Initiator... picker in Add Host finds no WWPNs, because the appliance has no initiator role with which to see the fabric. You can still create a host by typing the initiator's WWPN in by hand. Use target-only mode only where that trade-off is intended.
Do not edit the driver configuration by hand
Older guidance had administrators write the modprobe file directly. Two values in common circulation are wrong:
| Value | What it actually does |
|---|---|
qlini_mode=enabled |
Initiator only -- not dual mode. |
qlini_mode=disabled |
The initiator role is never created. A port taken out of target mode then has no role at all, which breaks Enable FC Initiator Mode. |
Hand-written instructions also commonly use the filename /etc/modprobe.d/qla2xxx_scst.conf, while qs-util writes /etc/modprobe.d/qla2xxx.conf. Following both leaves two files setting the same option to different values, and which one wins is not something to rely on. If you have an old qla2xxx_scst.conf on an appliance, remove it and set the mode with qs-util.
Related pages
- Fibre Channel Target Port Management -- FC target ports, remote ports, LIPs and assigning volumes over FC
- Hosts and Host Groups -- host records and FC WWPN initiators
- QuantaStor Shell Utilities --
qs-utiland the other appliance command-line tools
Verified against QuantaStor 6.9.0.