Configuring the drive loops, Configuring, Drive – IBM TOTALSTORAGE DS4500 User Manual
Page 10: Loops, Figure
Configuring
the
drive
loops
The
procedure
and
illustrations
in
this
section
show
how
to
connect
one
group
of
four
storage
expansion
enclosures
in
a
redundant
drive
loop.
Instructions
for
how
to
connect
a
second
group
of
four
storage
expansion
enclosures
in
a
redundant
drive
loop
are
also
included
in
this
procedure.
To
complete
this
procedure,
you
will
need
two
fiber-optic
cables
per
storage
expansion
enclosure.
Attention:
Handle
and
install
fiber-optic
cables
properly
to
avoid
degraded
performance
or
loss
of
communications
with
devices.
Do
not
overtighten
the
cable
straps
or
bend
the
cables
to
a
diameter
of
less
than
76
mm
(3
in.),
or
a
radius
less
than
38
mm
(1.5
in.).
1.
Connect
the
first
two
storage
expansion
enclosures
to
drive
loop
A,
as
shown
in
Starting
with
the
first
storage
expansion
enclosure,
connect
a
fiber-optic
cable
from
the
In
port
on
the
left
environmental
services
module
(ESM)
board
to
the
Out
port
on
the
left
ESM
board
in
the
second
(next)
storage
expansion
enclosure.
Drive Loop A
Drive Loop B
Drive Loop A Fibre
Channel interface
Cables
Drive Loop B Fibre
Channel interface
Cables
First DS4000 drive
enclosure
Last DS4000 drive
enclosure
Storage Expansion
Enclosures -
Group 1
DS4500 Storage
Subsystem
Input
Input
Output
Output
Drive minihub 1
Drive minihub 2
ds452min
Figure
8.
Redundant
drive
loop
cabling
overview
with
two
mini
hubs
in
slots
1
and
2
—
Not
for
use
unless
you
meet
the
requirements
in
the
above
Note
10