BIOS vs Linux RAID

BIOS vs Linux RAID

The Question

Every few weeks, we get somebody asking the question:

"Why don't you just use the RAID that's on the motherboard?"

or,

"But I thought this Intel C612C Chipset [or many others] came with RAID built in?"

The Misconception

Well, even though this practice has been around for many years, it's important that we explain, again, what this is -

It is BIOS-assisted software RAID, proprietary, and non-standard.

It's also commonly known as "Fake RAID" in many circles - see "Further Reading,", below.

The Solution

There's nothing inherently wrong with CPU-assisted (aka software) RAID, but you should use the software RAID that's built into Linux or BSD - it's tested, tried and true, open source, and standard.

We recommend Linux Software RAID, (optionally, with LVM).

"Motherboard RAID", also known as "Fake RAID", is (almost always) merely BIOS-assisted software RAID, implemented in firmware - and is closed-source, proprietary, non-standard, and often buggy, and almost always slower than the time-tested and reliable software RAID found in Linux.

Reading code from the BIOS is several times slower than reading code from main memory, which is one of the reasons why benchmarks have repeatedly shown Linux built-in OS RAID outperforms BIOS RAID repeatedly - and is of course compatible across disks, motherboards, and so forth.

Plus, if the motherboard fails, that you're using the BIOS RAID from, you're stuck having to find an identical motherboard, because the proprietary firmware RAID implementations are often not compatible.

Further reading

https://help.ubuntu.com/community/FakeRaidHowto
https://wiki.archlinux.org/index.php/Installing_with_Fake_RAID
https://ata.wiki.kernel.org/index.php/SATA_RAID_FAQ

Contact Us

Let us know if you have any additional questions - we configure software RAID for customers all the time.

Contact us today with questions or comments, info@eracks.com.

2026 Update: the Question Has a New Costume

The modern version of "but the motherboard has RAID built in" is NVMe fake RAID: Intel VROC and VMD, and the various vendor firmware-RAID modes for M.2 and U.2 drives. The answer has not changed. It is still firmware-assisted software RAID, still proprietary, still non-portable (your array is married to that board family), and still slower or no faster than the open, portable equivalents built into Linux and BSD.

What HAS changed is that the best answer got better: ZFS gives you pooling, checksumming, snapshots, and self-healing that neither fake RAID nor classic mdraid can match, and it wants exactly what we ship: raw drives on an IT-mode HBA or direct NVMe lanes, no proprietary controller in the way. See RAID Levels for the layout map and our free ZFS Layout Guide for which pool to build.