emx(7)

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emx(7)
NAME
  emx - Device Driver for the Emulex Fibre Channel Host Adapter

SYNOPSIS
  bus emx0 at pci?  controller scsiX at emx0
  bus emx1 at pci?  controller scsiY at emx1
   .
   .
   .
  bus emxN at pci?  controller scsiZ at emxN

DESCRIPTION
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       An updated version of this page, and the emx.data.c(4) page can
       be found at:
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  The emx driver controls and manages the Emulex Fibre Channel Host Adapter.
  The emx driver is fully integrated with the CAM SCSI I/O subsystem to
  provide connnectivity to FCP (e.g. SCSI) devices attached via the Fibre
  Channel adapter. In addition to acting as an FCP initiator, the emx driver
  also functions as a FCP target. CAM Target Mode peripheral drivers are also
  supported.

  In most cases, FCP on Fibre Channel (FC) maps very well into the existing
  paradigms for Parallel SCSI and SCSI-2. However, one area that differs is
  is in addressing. Parallel SCSI commonly has fixed Target ids and the range
  of Target Ids is small. Fibre Channel on the other hand, has a large
  address capacity (2^24 bits - over 16 million addresses) and the addresses
  are not necessarily fixed.  To support high availability, a device may
  commonly change its physical FC address as it moves between redundant
  components. Complicating this issue is that the physical Target Ids of
  parallel SCSI are exposed in the namespace of the SCSI disk and tape
  drivers.

  To deal with non-persistent and high capacity physical addresses, the emx
  driver uses a low-level Fibre Channel world wide name to identify a device.
  The emx driver assigns a target id to each world wide name it sees  (on a
  FIFO basis) and translates the Target Id to the physical address as i/o
  requests are issued to the Fibre Channel interconnect. Thus, regardless of
  the physical address the device uses, it is always seen at the same Target
  Id to CAM. The emx driver saves the world wide name to Target Id mappings
  for each adapter to an on disk database (/etc/emx.db). The database allows
  for the mapping to remain persistent across power cycles and reboots. A
  human readable form of this file is also written to /etc/emx.info. If you
  need to modify any Target Id mappings, you can do so via
  /sys/data/emx_data.c (see emx_data.c(4)).  Note that this persistence model
  implies that that you must change the driver Target Id mappings whenever a
  device is swapped out with a replacement and/or permanently removed from
  the FC configuration.

				     Note

       As target id mappings are assigned per adapter on a first-
       seen/first assigned basis, it is quite likely that the same
       storage entity attached to 2 adapters will be assigned different
       target ids.

  As the CAM SCSI disk and tape subsystems are limited by their SCSI-2
  namespace, only 8 target id's can been seen via the emx driver. The driver
  may assign devices target ids beyond the 0-7 range. If the driver does so,
  it will announce that the device is invisible to the CAM via a console
  message and/or error log entry. As the adapter responds as a target device
  on the FC interconnect, it will typically consume one of the 8 available
  target ids (as will any other adapters also on the same FC interconnect).

  The emx driver currently provides Class 3 operation in a Switch-based
  Fabric configuration.

RESTRICTIONS
  FC storage devices cannot be used for boot, dump, or swap. FC devices are
  supported as a data-only devices.

  Due to the way sense data is handled in FCP, CAM SCSIIO CCB's that have
  AUTOSENSE disabled (CAM_DIS_AUTOSENSE) will be rejected with a
  CAM_PROVIDE_FAIL status.

  Only a Point-to-Point connection to a FC switch is supported. Direct
  connections without an intervening switch are not supported.

  Although functional, Arbitrated Loop configurations are not supported.

  Due to the SCSI-2 limitations inherent in the design of Target Mode
  operation in the CAM specification, specifically in the area of sense data
  handling, Tagged Command Queuing is not supported in the Target Mode
  portion of the emx driver.

FILES
  /sys/BINARY/emx.mod
    The device driver module.

  /sys/data/emx_data.c
    Configuration file for the emx device driver. Allows the manipulation of
    CAM Target Id to FC N*Port mappings.

  /etc/emx.db
    The binary file containing the persistent CAM Target Id to Fibre Channel
    N*_Ports mappings for each emx adapter.

  /etc/emx.db.bak
    A backup copy of the /etc/emx.db file.

  /etc/emx.info
    Text file representing the contents of the /etc/emx.db file. This is a
    readable form of the persistent CAM Target Id to Fibre Channel N*_Ports
    mappings for each emx adapter. Note that this file does not reflect
    current connectivity, as devices may not be present, but their Target Id
    mappings will continue to persist.

RELATED INFORMATION
  SCSI(7), rz(7).

  See Also

  emx_data.c(4).
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