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
understand 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. Ad

ditionally, the
atacontrol(8) utility can be used to create, rebuild, update

and fail
such RAID arrays.

The ataraid driver can read the following metadata formats:

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

The ataraid driver can write the following metadata formats:

+o Highpoint V2 RocketRAID
+o Intel MatrixRAID
+o JMicron
+o Promise FastTrak
+o Silicon Integrated Systems (SiS)
+o VIA Tech V-RAID
+o 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)

CAVEATS

RAID5 is not supported at this time. Code exists, but it

neither uses
nor maintains parity information.

AUTHORS

The ataraid driver was written by Soren Schmidt <sos@FreeB

SD.org>. This
manual page was written by Christian Brueffer <bruef

fer@FreeBSD.org>.

BSD February 17, 2006

BSD