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Matrix RAID is a computer storage technology marketed by Intel. It is a firmware, rather than hardware or software, RAID system.
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Matrix RAID first appeared in the ICH6R "southbridge" chip. Intel uses an 'R' at the end of the southbridge's name – ICH9R instead of ICH9 – to indicate when a southbridge contains their Matrix RAID technology and no other upgrades. Complicating the matter is that instead of "R," a "DO," "DH," etc. has indicated a southbridge that combined RAID with non-RAID-related upgrades to the southbridge. Newer chipsets which do not use a separate southbridge might also use Intel RST without explicit extensions like "R" within the chipset name; an example for this is the Intel PCH C200 chipset series. Like all RAID, Intel Matrix RAID employs two or more physical hard disks which the operating system will treat as a single disk, in order to increase redundancy which avoids data loss (as all RAID levels except RAID 0 do), and/or to increase the speed at which data is written to and/or read from a disk.
Intel Matrix RAID is not a new RAID level. It allows different areas (e.g. partitions or logical volumes) on the same disk to be assigned to different RAID devices, unlike some other RAID controllers. The ICH10R supports RAID 0, RAID 1, RAID 10, and RAID 5.
Intel recommends to put any critical applications and data on a RAID 1, 5, or 10 volume, with redundancy to protect against data loss. The RAID 0 volume in Matrix RAID provides fast access to large files where data loss is not a critical issue but speed is; examples include video editing, swap files, and files that are backed up.
Intel Matrix RAID, Intel Rapid RAID, and Intel Smart Response Technology are together described as Intel Rapid Storage Technology.
Operating system support
Linux supports Matrix RAID through device mapper (DM-RAID) for RAID 0, 1 and 10, and Linux MD RAID for RAID 0, 1, 10, and 5. Set up of the RAID volumes must be done by using the ROM option in the Matrix Storage Manager, then further configuration can be done in DM-RAID or MD-RAID.
FreeBSD and MidnightBSD support Intel Matrix RAID using the ataraid driver, managed through the atacontrol command. However, with older versions of FreeBSD there are critical reliability issues which include array device renaming when a disk in an array is replaced, an array being considered healthy if the machine reboot/crashes during an array rebuild, and kernel panics when a disk is lost or is removed from the bus. Some of these problems, when experienced in combination, could result in the loss of an entire array (even in the case of RAID 1).
Microsoft Windows has full support for Intel Matrix RAID, including creation of RAID volumes.
VMware ESXi 4 does not support any RAID function nor Intel Matrix RAID based on Intel ICHxR controllers.
PGPDisk does not support Intel Matrix RAID based on Intel ICHxR, and does not support standalone drives if the "RAID" mode is enabled on the motherboard.
Matrix Storage Manager option ROM
The Intel Matrix Storage Manager (IMSM) option ROM is a part of Matrix RAID that has to be used in the BIOS to create new RAID arrays. As of 2014 Intel uses "Rapid Storage Technology" -"Option Rom"- on its new chipsets, dropping the "Matrix" name. An Intel document notes that Matrix RAID storage changed to RST (Rapid Storage Technology) beginning with version 9.5.
There are several versions available:
Since release 11.2.0.0000, TRIM commands can be read by Windows RAID drivers made for 7 series chipsets. There is no TRIM support on drivers for older chipsets.
Intel states that RST support has been added for the X79 chipset in RST version 11.6.0.0000 and after. Contained in the RST Production Version Release Notes, contained here.
On some 6 series chipsets there is a modification which will add a modded ROM to the BIOS which will allow TRIM support on the 6 series chipset, contained here.
For the X79 chipset, certain motherboard manufacturers have added both RAID ROM's in the BIOS, the RST and RST-E ROM. X79 is the Enterprise version, called RST-E. With the RST ROM added to the BIOS, this allows TRIM function to pass through the controller and TRIM SSD drives. As there is no support for TRIM with the RST-E version of the ROM. If the motherboard manufacturer has not added the RST ROM to your BIOS, you can mod the BIOS with a modified ROM for the X79, that only contains the RST-E ROM.
The newest Option ROM version is a 13 series ROM, this ROM will not be used by motherboard manufacturers for the X79 chipset BIOS, and it can be injected into a BIOS to use on the X79 with modded code, for those MFG's who have added a ROM switch, this is where the MFG has added both RST and RSTe to the RAID option of a BIOS, but there needs to be a code added for TRIM commands to be sent, when you inject the RST and replace the RSTe with RST option ROM in X79 boards that do not contain the ROM switch, TRIM can be dysfunctional.
There are modded RST 13 series Option ROMs (legacy) available at certain BIOS modding sites that have been made functional for use in the X79 chipsets.
When booting in a BIOS environment (legacy) and some / EFI, the RST option ROM is used. When booting in a true UEFI environment the Option ROM is not used as a SataDriver with the RST version takes over. In BIOS mode the legacy/BIOS booting is under CSMCORE. In true UEFI mode the RST is controlled under SataDriver in BIOS.
The Intel RAID ROM is the firmware in the motherboard BIOS that is used to create the RAID array.
Note: The RST drivers can be used for RAID and also on a single drive as it contains an AHCI driver. There is a bug in the version 12.5.0.1066 RST driver, which cause TRIM commands not to pass through the RAID driver to the drives. TRIM is disabled using this driver.