Chapter 4 Connect the Front End
100
Storage Center SC8000 Controller Deployment Guide
Example Legacy Mode Configuration
The
following
figure
shows
a
dual
‐
controller
Storage
Center
in
legacy
mode
connected
to
a
Fibre
Channel
server
with
two
fault
domains.
Fault
domain
1
(shown
in
orange)
is
comprised
of
primary
port
P1
on
controller
A
and
reserved
port
R1
on
controller
B.
Fault
domain
2
(shown
in
green)
is
comprised
of
primary
port
P2
on
controller
B
and
reserved
port
R2
on
controller
A.
Figure 89. Legacy Mode Example with FC
The
following
table
summarizes
the
failover
behaviors
for
this
configuration.
Note:
To
use
multiple
paths
simultaneously,
the
server
must
be
configured
to
use
MPIO.
Scenario
Failover Behavior
Normal
operating
conditions • Primary
ports
P1
and
P2
(both
fault
domains)
pass
IO.
• Reserved
ports
R1
and
R2
remain
in
a
standby
mode
until
a
controller
failure.
Controller
A
fails
In
fault
domain
1,
primary
port
P1
fails
over
to
reserved
port
R1.
Controller
B
fails
In
fault
domain
2,
primary
port
P2
fails
over
to
reserved
port
R2.
A
single
port
fails
The
port
does
not
fail
over
because
there
was
no
controller
failure.
If
a
second
path
is
available,
MPIO
software
on
the
server
provides
fault
tolerance
by
sending
IO
to
the
functioning
port
in
the
other
fault
domain.
Controller A
FC Switch
Server
Controller B
Primary Port — P2
Primary Port — P1
Reserved Port — R1
Reserved Port — R2
