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ATARAID(4)		     Kernel Interfaces Manual		      ATARAID(4)

NAME
     ataraid -- ATA software RAID support

SYNOPSIS
     device ata
     device ataraid

DESCRIPTION
     The  ataraid driver provides support for so-called software RAID (sometimes
     referred to as fake RAID or pseudo RAID).

     When a controller that supports software RAID is  instructed  to  create  a
     RAID  array,  its BIOS writes data structures in a specific metadata format
     to the disks.  These data structures are picked up by the	ataraid  driver,
     so  that FreeBSD can work with the array.	The ataraid driver has to under-
     stand the specific metadata format of a controller BIOS in order to support
     its RAID capabilities.

     Read-only support for a metadata format means  that  FreeBSD  can	use  the
     given RAID array for normal read/write operations.  Creation and rebuild of
     such arrays has to be done from the controller BIOS.

     Read and write support for a metadata format means that FreeBSD can use the
     given  RAID array for normal read/write operations.  Additionally, the ata-
     control(8) utility can be used to create, rebuild,  update  and  fail  such
     RAID arrays.

     The ataraid driver can read the following metadata formats:

     *	 Adaptec HostRAID
     *	 Highpoint V2 RocketRAID
     *	 Highpoint V3 RocketRAID
     *	 Intel MatrixRAID
     *	 Integrated Technology Express (ITE)
     *	 JMicron
     *	 LSI Logic V2 MegaRAID
     *	 LSI Logic V3 MegaRAID
     *	 NVIDIA MediaShield
     *	 Promise FastTrak
     *	 Silicon Image Medley
     *	 Silicon Integrated Systems (SiS)
     *	 VIA Tech V-RAID
     *	 FreeBSD PseudoRAID

     The ataraid driver can write the following metadata formats:

     *	 Highpoint V2 RocketRAID
     *	 Intel MatrixRAID
     *	 JMicron
     *	 Promise FastTrak
     *	 Silicon Integrated Systems (SiS)
     *	 VIA Tech V-RAID
     *	 FreeBSD PseudoRAID

     It  is  also  possible to use software RAID on controllers that do not have
     special software RAID capabilities.  See atacontrol(8) for details.

FILES
     /dev/ar*  ATA RAID device nodes

SEE ALSO
     ata(4), atacontrol(8)

AUTHORS
     The ataraid driver was written by Soren  Schmidt  <sos@FreeBSD.org>.   This
     manual page was written by Christian Brueffer <brueffer@FreeBSD.org>.

CAVEATS
     RAID5  is not supported at this time.  Code exists, but it neither uses nor
     maintains parity information.

FreeBSD 9.0			February 17, 2006		      ATARAID(4)

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