mrsas(4) LSI MegaRAID 6Gb/s and 12Gb/s SAS+SATA RAID controller driver


To compile this driver into the kernel, place the following lines in your kernel configuration file:
device pci device mrsas

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf5:



The driver will detect LSI's next generation (6Gb/s and 12Gb/s) PCI Express SAS/SATA RAID controllers. See the HARDWARE section for the supported devices list. A disk (virtual disk/physical disk) attached to the driver will be visible to the user through camcontrol(8) as /dev/da? device nodes. A simple management interface is also provided on a per-controller basis via the /dev/mrsas? device node.

The name is derived from the phrase "MegaRAID SAS HBA", which is substantially different than the old "MegaRAID" Driver mfi(4) which does not connect targets to the cam(4) layer and thus requires a new driver which attaches targets to the cam(4) layer. Older MegaRAID controllers are supported by mfi(4) and will not work with , but both the mfi(4) and drivers can detect and manage the LSI MegaRAID SAS 2208/2308/3008/3108 series of controllers.

The device.hints5 option is provided to tune the driver's behavior for LSI MegaRAID SAS 2208/2308/3008/3108 controllers. By default, the mfi(4) driver will detect these controllers. See the PRIORITY section to know more about driver priority for MR-Fusion devices.

will provide a priority of (-30) (between BUS_PROBE_DEFAULT and BUS_PROBE_LOW_PRIORITY at probe call for device id's 0x005B, 0x005D, and 0x005F so that does not take control of these devices without user intervention.


The driver supports the following hardware:

[ Thunderbolt 6Gb/s MR controller ]

  • LSI MegaRAID SAS 9265
  • LSI MegaRAID SAS 9266
  • LSI MegaRAID SAS 9267
  • LSI MegaRAID SAS 9270
  • LSI MegaRAID SAS 9271
  • LSI MegaRAID SAS 9272
  • LSI MegaRAID SAS 9285
  • LSI MegaRAID SAS 9286
  • DELL PERC H810
  • DELL PERC H710/P

[ Invader/Fury 12Gb/s MR controller ]

  • LSI MegaRAID SAS 9380
  • LSI MegaRAID SAS 9361
  • LSI MegaRAID SAS 9341
  • DELL PERC H830
  • DELL PERC H730/P
  • DELL PERC H330


To disable Online Controller Reset(OCR) for a specific driver instance, set the following tunable value in loader.conf5:

where X is the adapter number.

To change the I/O timeout value for a specific driver instance, set the following tunable value in loader.conf5:


where NNNNNN is the timeout value in milli-seconds.

To change the firmware fault check timer value for a specific driver instance, set the following tunable value in loader.conf5:


where NN is the fault check delay value in seconds.

The current number of active I/O commands is shown in the dev.mrsas.X.fw_outstanding sysctl(8) variable.


To enable debugging prints from the driver, set the hw.mrsas.X.debug_level variable, where X is the adapter number, either in loader.conf5 or via sysctl(8). The following bits have the described effects:

Enable informational prints.
Enable tracing prints.
Enable prints for driver faults.
Enable prints for OCR and I/O timeout.
Enable prints for AEN events.


The driver will always set a default (-30) priority in the PCI subsystem for selection of MR-Fusion cards. (It is between BUS_PROBE_DEFAULT and BUS_PROBE_LOW_PRIORITY ) MR-Fusion Controllers include all cards with the Device IDs - 0x005B, 0x005D, 0x005F.

The mfi(4) driver will set a priority of either BUS_PROBE_DEFAULT or BUS_PROBE_LOW_PRIORITY (depending on the device.hints setting) in the PCI subsystem for selection of MR-Fusion cards. With the above design in place, the mfi(4) driver will attach to a MR-Fusion card given that it has a higher priority than .

Using /boot/device.hints (as mentioned below), the user can provide a preference for the driver to detect a MR-Fusion card instead of the mfi(4) driver.


At boot time, the mfi(4) driver will get priority to detect MR-Fusion controllers by default. Before changing this default driver selection policy, LSI advises users to understand how the driver selection policy works. LSI's policy is to provide priority to the mfi(4) driver to detect MR-Fusion cards, but allow for the ability to choose the driver to detect MR-Fusion cards.

LSI recommends setting hw.mfi.mrsas_enable="0" for customers who are using the older mfi(4) driver and do not want to switch to . For those customers who are using a MR-Fusion controller for the first time, LSI recommends using the driver and setting hw.mfi.mrsas_enable="1".

Changing the default behavior is well tested under most conditions, but unexpected behavior may pop up if more complex and unrealistic operations are executed by switching between the mfi(4) and drivers for MR-Fusion. Switching drivers is designed to happen only one time. Although multiple switching is possible, it is not recommended. The user should decide from Start of Day which driver they want to use for the MR-Fusion card.

The user may see different device names when switching from mfi(4) to . This behavior is Functions As Designed and the user needs to change the fstab(5) entry manually if they are doing any experiments with mfi(4) and interoperability.


array/logical disk interface
management interface


The driver first appeared in Fx 10.1 . mfi Driver: mfi(4) is the old Fx driver which started with support for Gen-1 Controllers and was extended to support up to MR-Fusion (Device ID = 0x005B, 0x005D, 0x005F). mrsas Driver: is the new driver reworked by LSI which supports Thunderbolt and onward products. The SAS+SATA RAID controller with device id 0x005b is referred to as the Thunderbolt controller throughout this man page. cam aware HBA drivers: Fx has a cam(4) layer which attaches storage devices and provides a common access mechanism to storage controllers and attached devices. The driver is cam(4) aware and devices associated with can be seen using camcontrol(8). The mfi(4) driver does not understand the cam(4) layer and it directly associates storage disks to the block layer.

Thunderbolt Controller: This is the 6Gb/s MegaRAID HBA card which has device id 0x005B.

Invader Controller: This is 12Gb/s MegaRAID HBA card which has device id 0x005D.

Fury Controller: This is the 12Gb/s MegaRAID HBA card which has device id 0x005F.


The driver and this manual page were written by An Kashyap Desai Aq [email protected] .


The driver does not support big-endian architectures at this time.

The driver does not support alias for device name (it is required when the user switches between two drivers and does not want to edit /etc/fstab manually).

The driver exposes devices as /dev/da? whereas mfi(4) exposes devices as /dev/mfid?

does not support the Linux Emulator interface.

will not work with mfiutil(8).