Adaptec AEC-4412B Instrukcja Użytkownika Pobierz pdf (Strona 6)

CQ-1001 / Page 6 of 14

US

6,425,035

B2

5

tions

more

easily.

This

is

accomplished

without

limiting

the

performance

of

workstations

58

because

storage

access

involves

native

low

level,

block

protocols

and

does

not

involve

the

overhead

of

high

level

protocols

and

file

systems

required

by

network

servers.

FIG.

4

is

a

block

diagram

of

one

embodiment

of

storage

router

56

of

FIG.

3.

Storage

router

56

can

comprise

a

Fiber

Channel

controller

80

that

interfaces

with

Fiber

Channel

52

and

a

SCSI

controller

82

that

interfaces

with

SCSI

bus

54.

Abuffer

84

provides

memory

work

space

and

is

connected

to

both

Fiber

Channel

controller

80

and

to

SCSI

controller

82.

A

supervisor

unit

86

is

connected

to

Fiber

Channel

controller

80,

SCSI

controller

82

and

buffer

84.

Supervisor

unit

86

comprises

a

microprocessor

for

controlling

operation

of

storage

router

56

and

to

handle

mapping

and

security

access

for

requests

between

Fiber

Channel

52

and

SCSI

bus

54.

FIG.

5

is

a

block

diagram

of

one

embodiment

of

data

flow

within

storage

router

56

of

FIG.

4.

As

shown,

data

from

Fiber

Channel

52

is

processed

by

a

Fibre

Channel

(FC)

protocol

unit

88

and

placed

in

a

FIFO

queue

90.

A

direct

memory

access

(DMA)

interface

92

then

takes

data

out

of

FIFO

queue

90

and

places

it

in

buffer

84.

Supervisor

unit

86

processes

the

data

in

buffer

84

as

represented

by

supervisor

processing

93.

This

processing

involves

mapping

between

Fiber

Channel

52

and

SCSI

bus

54

and

applying

access

controls

and

routing

functions.

A

DMA

interface

94

then

pulls

data

from

bufier

84

and

places

it

into

a

buffer

96.

A

SCSI

protocol

unit

98

pulls

data

from

buffer

96

and

communicates

the

data

on

SCSI

bus

54.

Data

flow

in

the

reverse

direction,

from

SCSI

bus

54

to

Fiber

Channel

52,

is

accomplished

in

a

reverse

manner.

The

storage

router

of

the

present

invention

is

a

bridge

device

that

connects

a

Fiber

Channel

link

directly

to

a

SCSI

bus

and

enables

the

exchange

of

SCSI

command

set

infor-

mation

between

application

clients

on

SCSI

bus

devices

and

the

Fiber

Channel

links.

Further,

the

storage

router

applies

access

controls

such

that

virtual

local

storage

can

be

estab-

lished

in

remote

SCSI

storage

devices

for

workstations

on

the

Fiber

Channel

link.

In

one

embodiment,

the

storage

router

provides

a

connection

for

Fiber

Channel

links

running

the

SCSI

Fiber

Channel

Protocol

(FCP)

to

legacy

SCSI

devices

attached

to

a

SCSI

bus.

The

Fiber

Channel

topology

is

typically

an

Arbitrated

Loop

(FCiAL).

In

part,

the

storage

router

enables

a

migration

path

to

Fiber

Channel

based,

serial

SCSI

networks

by

providing

connectivity

for

legacy

SCSI

bus

devices.

The

storage

router

can

be

attached

to

a

Fiber

Channel

Arbitrated

Loop

and

a

SCSI

bus

to

support

a

number

of

SCSI

devices.

Using

configuration

settings,

the

storage

router

can

make

the

SCSI

bus

devices

available

on

the

Fiber

Channel

network

as

FCP

logical

units.

Once

the

configuration

is

defined,

operation

of

the

storage

router

is

transparent

to

application

clients.

In

this

manner,

the

storage

router

can

form

an

integral

part

of

the

migration

to

new

Fibre

Channel

based

networks

while

providing

a

means

to

continue

using

legacy

SCSI

devices.

In

one

implementation

(not

shown),

the

storage

router

can

be

a

rack

mount

or

free

standing

device

with

an

internal

power

supply.

The

storage

router

can

have

a

Fibre

Channel

and

SCSI

port,

and

a

standard,

detachable

power

cord

can

be

used,

the

FC

connector

can

be

a

copper

DB9

connector,

and

the

SCSI

connector

can

be

a

68-pin

type.

Additional

modular

jacks

can

be

provided

for

a

serial

port

and

a

802.3

10BaseT

port,

i.e.

twisted

pair

Ethernet,

for

management

access.

The

SCSI

port

of

the

storage

router

an

support

SCSI

direct

and

sequential

access

target

devices

and

can

support

SCSI

10

15

20

25

30

35

40

45

50

55

60

65

6

initiators,

as

well.

The

Fiber

Channel

port

can

interface

to

SCSI-3

FCP

enabled

devices

and

initiators.

To

accomplish

its

functionality,

one

implementation

of

the

storage

router

uses:

a

Fiber

Channel

interface

based

on

the

HEWLETT-PACKARD

TACHYON

HPFC-5000

con-

troller

and

a

GLM

media

interface;

an

Intel

80960RP

processor,

incorporating

independent

data

and

program

memory

spaces,

and

associated

logic

required

to

implement

a

stand

alone

processing

system;

and

a

serial

port

for

debug

and

system

configuration.

Further,

this

implementation

includes

a

SCSI

interface

supporting

Fast-20

based

on

the

SYMBIOS

53C8xx

series

SCSI

controllers,

and

an

operat-

ing

system

based

upon

the

WIND

RIVERS

SYSTEMS

VXWORKS

or

IXWORKS

kernel,

as

determined.

by

design.

In

addition,

the

storage

router

includes

software

as

required

to

control

basic

functions

of

the

various

elements,

and

to

provide

appropriate

translations

between

the

FC

and

SCSI

protocols.

The

storage

router

has

various

modes

of

operation

that

are

possible

between

FC

and

SCSI

target

and

initiator

combi-

nations.

These

modes

are:

FC

Initiator

to

SCSI

Target;

SCSI

Initiator

to

FC

Target;

SCSI

Initiator

to

SCSI

Target;and

FC

Initiator

to

FC

Target.

The

first

two

modes

can

be

supported

concurrently

in

a

single

storage

router

device

are

discussed

briefly

below.

The

third

mode

can

involve

two

storage

router

devices

back

to

back

and

can

serve

primarily

as

a

device

to

extend

the

physical

distance

beyond

that

possible

via

a

direct

SCSI

connection.

The

last

mode

can

be

used

to

carry

FC

protocols

encapsulated

on

other

transmission

technologies

(e.g.

ATM,

SONET),

or

to

act

as

a

bridge

between

two

FC

loops

(e.g.

as

a

two

port

fabric).

The

FC

Initiator

to

SCSI

Target

mode

provides

for

the

basic

configuration

of

a

server

using

Fiber

Channel

to

communicate

with

SCSI

targets.

This

mode

requires

that

a

host

system

have

an

FC

attached

device

and

associated

device

drivers

and

software

to

generate

SCSI-3

FCP

requests.

This

system

acts

as

an

initiator

using

the

storage

router

to

communicate

with

SCSI

target

devices.

The

SCSI

devices

supported

can

include

SCSI-2

compliant

direct

or

sequential

access

(disk

or

tape)

devices.

The

storage

router

serves

to

translate

command

and

status

information

and

transfer

data

between

SCSI-3

FCP

and

SCSI-2,

allowing

the

use

of

standard

SCSI-2

devices

in

a

Fibre

Channel

environ-

ment.

The

SCSI

Initiator

to

FC

Target

mode

provides

for

the

configuration

of

a

server

using

SCSI-2

to

communicate

with

Fiber

Channel

targets.

This

mode

requires

that

a

host

system

has

a

SCSI-2

interface

and

driver

software

to

control

SCSI-2

target

devices.

The

storage

router

will

connect

to

the

SCSI-2

bus

and

respond

as

a

target

to

multiple

target

IDs.

Configu-

ration

information

is

required

to

identify

the

target

IDs

to

which

the

bridge

will

respond

on

the

SCSI-2

bus.

The

storage

router

then

translates

the

SCSI-2

requests

to

SCSI-3

FCP

requests,

allowing

the

use

of

FC

devices

with

a

SCSI

host

system.

This

will

also

allow

features

such

as

a

tape

device

acting

as

an

initiator

on

the

SCSI

bus

to

provide

full

support

for

this

type

of

SCSI

device.

In

general,

user

configuration

of

the

storage

router

will

be

needed

to

support

Various

functional

modes

of

operation.

Configuration

can

be

modified,

for

example,

through

a

serial

port

or

through

an

Ethernet

port

via

SNMP

(simple

network

management

protocol)

or

a

Telnet

session.

Specifically,

SNMP

manageability

can

be

provided

via

an

802.3

Ethernet

interface.

This

can

provide

for

configuration

changes

as

well

as

providing

statistics

and

error

information.

Configuration

can

also

be

performed

via

TELNET

or

RS-232

interfaces

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