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ri(7)


NAME

  ri - I2O RAID disk interface


SYNOPSIS

  bus		  i2o0	     at pci2001	  slot	4

  controller	  i2o_bs0    at i2o0	  slot	18


DESCRIPTION

  The ri driver supports 32-bit and 64-bit PCI backplane RAID controllers
  with Intelligent I/O (I2O) host interface supporting backend SCSI channels.
  I2O is an open architecture for developing device drivers that is
  independent of the operating system, processor platform, and system I/O
  bus.	The communication model is based on a message-passing protocol
  reducing the number of driver interfaces needed.  A single driver called an
  Operating System Module(OSM) is provided to support all Block Storage class
  devices.  Any RAID system that supports the I2O interface functions with
  this driver.	These devices are designated as ri to distinguish them from
  ra, re, and rz (SCSI) devices.

  The StorageWorks Command Console Utility (SWCC) is supported for online
  configuration and monitoring of I2O raid devices.

  The following rules are used to determine the major and minor numbers that
  are associated with an ri type disk.	A dynamic major number is used to
  represent ri block devices, and is assigned during initial configuration.
  The current major number can be determined using the following command:

       # /sbin/devswmgr -getnum i2o_bs

  The preceding command displays the driver switch reservation list, showing
  the device instance and major number for the i2o_bs driver.  An alternative
  method is:

       # /sbin/sysconfig -q i2o_bs

  The highest 14 bits of the 20-bit minor number represents a particular
  Block Storage device, while lowest six bits of the minor number specify
  disk partitions (identified by the letters, a through h) on that device.

  The device special file names associated with ri disks are based on
  conventions that are closely associated with the minor number assigned to
  the disk.  The standard device names begin with ri for block special files
  and rri for character (raw) special files. Following the ri is the unit
  number and then a letter, a through h, that represents the partition.
  Throughout this reference page, the question mark (?) character represents
  the unit number in the name of the device special file.  For example, ri?b
  could represent ri0b, ri1b, and so on.

  A disk can be accessed through either the block special file or the
  character special file.  The block special file accesses the disk using the
  file system's normal buffering mechanism.  Reads and writes to the block
  special file can specify any size.  This capability avoids the need to
  limit data transfers to the size of physical disk records and to calculate
  offsets within disk records.	The file system can break up large read and
  write requests into smaller fixed size transfers to the disk.

  The character special file provides a raw interface that allows for direct
  transmission between the disk and the user's read or write buffer.  A
  single read/write operation to the raw interface results in exactly one I/O
  operation.  Consequently, raw I/O may be considerably more efficient for
  large transfers.

  For systems with ri disks, the first software boot after the system is
  powered on may take longer than expected.  This delay is normal and is
  caused by the software spinning up the ri disks.

  Disk Support

  The ri driver handles all disk drives that can be connected to the I2O RAID
  controller.  To determine which drives are supported for specific CPU types
  and hardware configurations, see the hardware installation and
  configuration information for your I2O system.

  I2O RAID Controllers are viewed in all cases as RI type disks. There are
  some notable differences that should be taken into consideration when
  configuring a RAID device:

    ·  Currently only sector sizes of 512 bytes are supported.

    ·  Logical Volume sizes are not fixed sizes as compared to other disk
       devices.	 The size of the Logical Volume is configurable based on
       needs.  The dynamic nature of Logical Volume sizes is dealt with by
       defining RAID devices as DYNAMIC.  Only partitions a, b, c, and g are
       defined.	 If necessary, the disklabel(8) command can be run to change
       and define partitions for RAID devices

  Usually, the ri?a partition is used for the root file system and the ri?b
  partition as a paging area.  The ri?c partition can be used for disk-to-
  disk copying because it maps the entire disk.

  The starting location and length (in 512 byte sectors) of the disk
  partitions of each drive are shown in the following table. Partition sizes
  can be changed by using the disklabel(8) command.

  I2O RAID partitions for systems based on the Alpha AXP architecture

	       disk    start   length
	       ri?a    0       131072
	       ri?b    131072  262144
	       ri?c    0       end of media
	       ri?d    0       0
	       ri?e    0       0
	       ri?f    0       0
	       ri?g    393216  end of media
	       ri?h    0       0


FILES

  /dev/disk/ri???

  /dev/disk/rri???


SEE ALSO

  RAID(7), SCSI(7), tz(7), rz(7), disklabel(8), MAKEDEV(8), uerf(8)

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