Chapter
1.
Introduction
This
chapter
describes
the
IBM
TotalStorage
DS4000
EXP700
and
DS4000
EXP710
storage
expansion
enclosure
operating
specifications,
features,
and
components.
This
chapter
also
includes
a
list
of
hardware
that
comes
with
the
storage
expansion
enclosure.
Note:
Throughout
this
document,
the
IBM
TotalStorage
DS4000
EXP700
storage
expansion
enclosure
is
referred
to
as
the
DS4000
EXP700
.
The
IBM
TotalStorage
DS4000
EXP710
storage
expansion
enclosure
is
referred
to
as
the
DS4000
EXP710
.
When
information
in
this
document
applies
to
both
the
DS4000
EXP700
and
DS4000
EXP710,
the
generic
term
storage
expansion
enclosure
is
used.
Overview
The
IBM
TotalStorage
DS4000
EXP700
(Machine
Type
1740,
Models
1RU
and
1RX)
and
DS4000
EXP710
(Machine
Type
1740,
Model
710)
storage
expansion
enclosures
provide
high-capacity,
fibre
channel
disk
storage.
Both
storage
expansion
enclosures
deliver
fast,
high-volume
data
transfer,
retrieval,
and
storage
functions
for
multiple
drives,
to
multiple
hosts.
The
storage
expansion
enclosures
provide
continuous,
reliable
service,
using
hot-swap
technology
for
easy
replacement
without
shutting
down
the
system.
Both
the
DS4000
EXP700
and
DS4000
EXP710
support
redundant,
dual-loop
configurations.
External
cables
and
Small
Form-Factor
Pluggable
(SFP)
modules
connect
the
controller
to
the
storage
expansion
enclosure.
The
DS4000
EXP710
Fibre
Channel
storage
expansion
enclosure
provides
improved
reliability
and
efficiency,
utilizing
internal
switch
technology
to
attach
to
each
disk
drive
within
the
DS4000
EXP710
storage
expansion
enclosure.
Within
the
DS4000
EXP710,
the
redundant
environmental
service
modules
(ESMs)
utilize
a
fibre
channel
switched
technology
attaching
directly
to
each
of
the
dual
ported
disk
drive
modules
for
additional
redundancy
and
high
availability.
1
The
DS4000
EXP710
fibre
channel
storage
expansion
enclosure
offers
the
following
diagnostic
and
performance
benefits:
v
Improved
diagnostic
capabilities
–
Provides
full
isolation
of
drives
–
Eliminates
the
risk
of
a
single
drive
disrupting
the
loop,
causing
other
drives
on
the
loop
to
fail
–
Enables
selective
diagnosis
of
fibre
channel
errors
–
Provides
a
platform
for
future
enhanced
diagnostic
and
serviceability
capabilities
v
Performance
1. The
DS4000
EXP710
uses
switched
JBOD
(or
switched
storage
expansion
enclosure)
technology
to
enable
an
enhanced
version
of
the
2
Gb/s
fibre
channel
JBOD.
The
primary
difference
between
a
switched
JBOD
and
a
JBOD
is
that
the
switched
JBOD
contains
a
fibre
channel
″
Loop
Switch
″
Application-Specific
Integrated
Circuit
(ASIC).
The
Loop
Switch
ASIC
allows
the
switched
JBOD
drives
and
any
connected
initiator
to
operate
as
though
they
were
on
a
private
Fibre
Channel
Arbitrated
Loop
(FC-AL),
while
retaining
the
performance
and
diagnostic
advantages
of
fibre
channel
fabric.
The
Loop
Switch
ASIC
allows
FC-AL
devices
to
communicate
directly
with
each
other
using
a
non-blocking
crossbar
switch,
which
reduces
the
loop
latency
inherent
in
a
true
arbitrated
loop.
Because
fibre
channel
communication
is
essentially
point-to-point
with
the
Loop
Switch
ASIC,
diagnosis
and
isolation
of
loop
problems
is
greatly
simplified.
The
advent
of
switched
JBOD
storage
expansion
enclosures
is
expected
to
be
a
significant
improvement
in
fibre
channel
based
storage
diagnostic
and
performance.
©
Copyright
IBM
Corp.
2005
1
Summary of Contents for TotalStorage DS4000 EXP710
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