---
name: "mfi"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/mfi"
---

# mfi(4)

LSI MegaRAID SAS driver

## NAME

**mfi** – LSI MegaRAID SAS driver

## SYNOPSIS

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

**device pci** **device mfi**

Alternatively, to load the driver as a module at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
mfi_load="YES"
```

## DESCRIPTION

This driver is for LSI's next generation PCI Express SAS RAID controllers. Access to RAID arrays (logical disks) from this driver is provided via */dev/mfid?* device nodes. A simple management interface is also provided on a per-controller basis via the */dev/mfi?* device node.

The **mfi** name is derived from the phrase "MegaRAID Firmware Interface", which is substantially different than the old "MegaRAID" interface and thus requires a new driver. Older SCSI and SATA MegaRAID cards are supported by [amr(4)](/amr/4.md) and will not work with this driver.

Two sysctls are provided to tune the **mfi** driver's behavior when a request is made to remove a mounted volume. By default the driver will disallow any requests to remove a mounted volume. If the sysctl *dev.mfi.%d.delete\_busy\_volumes* is set to 1, then the driver will allow mounted volumes to be removed.

A tunable is provided to adjust the **mfi** driver's behaviour when attaching to a card. By default the driver will attach to all known cards with high probe priority. If the tunable *hw.mfi.mrsas\_enable* is set to 1, then the driver will reduce its probe priority to allow [mrsas(4)](/mrsas/4.md) to attach to the card instead of **mfi**.

**mfi** does not provide ATA TRIM support. Refer to [mrsas(4)](/mrsas/4.md) if TRIM support is required.

## HARDWARE

The **mfi** driver supports the following hardware:

- LSI MegaRAID SAS 1078

- LSI MegaRAID SAS 8408E

- LSI MegaRAID SAS 8480E

- LSI MegaRAID SAS 9240

- LSI MegaRAID SAS 9260

- Dell PERC5

- Dell PERC6

- Fujitsu RAID Controller SAS 6Gbit/s 1GB (D3116)

- IBM ServeRAID M1015 SAS/SATA

- IBM ServeRAID M1115 SAS/SATA

- IBM ServeRAID M5015 SAS/SATA

- IBM ServeRAID M5110 SAS/SATA

- IBM ServeRAID-MR10i

- Intel RAID Controller SRCSAS18E

- Intel RAID Controller SROMBSAS18E

## FILES

- */dev/mfid?*

  array/logical disk interface

- */dev/mfi?*

  management interface

## DIAGNOSTICS

- mfid%d: Unable to delete busy device

  An attempt was made to remove a mounted volume.

## SEE ALSO

[amr(4)](/amr/4.md), [pci(4)](/pci/4.md), [mfiutil(8)](/mfiutil/8.md)

## HISTORY

The **mfi** driver first appeared in FreeBSD 6.1.

## AUTHORS

The **mfi** driver and this manual page were written by Scott Long ⟨*scottl@FreeBSD.org*⟩.

## BUGS

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