ATTO Technology 3100 - Manual (Page 20)

17 ATTO Technology BridgeTools Installation and Operation Manual
to 3, the FibreBridge will be at AL-PA 3 LUN 5 on all host
computers. The range of valid LUNs is 0 through 255. Most
operating systems can only scan for the LUNs 0 through
31and you should choose between these values.
If Address Translation is off, the FibreBridge LUN is set
from jumpers on the circuit board. The factory default
jumper value is LUN 14.
Fibre Channel Connect Mode (default = Arbitrated
Loop (FL_Port))
Sets the FibreBridge to either Arbitrated Loop (FL_Port)
mode or Point to Point (F_Port) mode. F_Port mode can
only be used when connecting directly to a F_Port on a host
adapter or a switch. FL_Port mode must be used when the
FibreBridge is connected to a hub or there are other devices
daisy chained off of the second GBIC port of the
FibreBridge. F_Port mode will result in slight performance
improvements. The initiator must be set to the same mode
as the FibreBridge for proper operation.
Fibre Channel Frame Length (default = 2048)
Modifies the maximum number of payload data bytes in a
Fibre Channel frame. Select 512 bytes, 1024 bytes or 2048
bytes. Experimenting with this value may increase
performance depending on both the application and
connected devices.
Open Full Duplex (default = Enabled)
Used to enable or disable Full Duplex transfer, a mode in
which a Fibre Channel port can receive and transmit data at
the same time, resulting in improved performance under
certain conditions. The initiator must also be set for Full
Duplex transfers.
Physical Device Addressing Method (default = LLLL
TTTB)
If the Address Translation field is set to enabled, modifies
the SCSI Address translation pattern for the FibreBridge.
The number of B, T and L bits defined in the pattern will
determine the number of FibreBridge busses, targets, and
LUNs addressed. The position of the B, T and L bits will
determine how they are mapped into the Fibre Channel
LUN. A binary translation is used to convert the eight BTL
bits into 256 possible unique Fibre Channel LUNs.
Using the default pattern of LLLL TTTB will allow two
FibreBridge busses to be addressed. One B bit can have a
value of 0 or 1. With three T bits, there is a possibility for
eight unique targets on each bus. Four LUN bits allow
sixteen LUNs on each target, on each bus. The decimal
value of this BTL byte is what is used to determine the Fibre
Channel LUN value of your connected SCSI device.
For example, if the addressing pattern is set to LLLL TTTB
and a SCSI drive is set at Target ID 4 LUN 0 connected to
FibreBridge bus 1. The B bit is set to binary 1, the T bits are
set to binary 4 (100), the L bits are set to binary 0 (0000).
The LLLL TTTB pattern will be filled in as 0000 1001
which translates to Fibre Channel LUN 9.
To modify the BTL pattern, click on the bar that contains the
BTL bits. An edit window will pop up.
Use the tool to select the position and number of bits for the
Bus, Target, and LUN bits. BridgeTools will indicate if an
inappropriate bit pattern is selected. Each BTL designator
can have any number of defined bits. Do not leave undefined
bits unless they are at the most significant positions. For
example, if only 5 bits need to be defined they must be in
positions 0 through 4. Leaving bit 0 undefined and then
assigning bits 1 through 5 is not allowed. Any one bit
position cannot be assigned to more than one BTL
designator. When more than one bit is required for any of
the B, T or L designators, they must be next to each other.
Three T bits must be assigned in consecutive positions.
A translation tool will help determine the Fibre Channel
LUN for a device. Click on the View FC LUNs tab. Find the
SCSI Target ID the device is set at down the left-hand
column. Find the SCSI LUN the device is set at (usually 0)
along the top. The Fibre Channel LUN is the value in the
green field that coincides with the devices SCSI ID and
LUN.
The table calculates the Fibre LUN based upon the current
BTL pattern set within the Editor tab, with a separate table
for devices connected to FibreBridge bus 1 and bus 2. The
grayed out LUNs are “unreachable” because this is the SCSI
ID the bridge SCSI port is set to. The Fibre Channel LUN in
red is the ID the FibreBridge itself will assume.
Refer to the Fibre Channel to SCSI Addressing chapter in
the FibreBridge manual or contact ATTO Technical Support
for further assistance.
Unprocessed SCSI Command Returns (default =
Queue Full)
Used to select the SCSI status command returned by the
FibreBridge when it is unable to accept a new command
from a host because of a temporary lack of internal
resources, a rare condition. This option is available because
some UNIX operating systems do not use the Queue Full
command and the FibreBridge will need to send a Busy
instead. Using Busy instead of Queue Full slows data
transfer rates.