The
following
notes
describe
the
Active
Memory
features:
v
Memory
mirroring
enables
you
to
improve
the
reliability
of
the
memory
in
your
server
by
creating
a
mirror
of
the
data
in
memory
port
1
and
storing
it
in
memory
port
2.
Note:
For
memory
mirroring
to
work,
you
must
have
DIMMs
of
the
same
size
and
clock
speed
in
both
memory
ports.
Complete
the
following
steps
to
enable
memory
mirroring:
1.
Check
your
operating
system
documentation
to
make
sure
that
it
supports
memory
mirroring.
2.
Install
DIMMs
of
the
same
size
and
clock
speed
in
the
two
memory
ports.
3.
Enable
memory
mirroring
in
the
Configuration/Setup
Utility
program:
a.
Turn
on
the
server
and
watch
the
monitor
screen.
b.
When
the
message
Press
F1
for
Configuration/Setup
appears,
press
F1.
c.
From
the
Configuration/Setup
Utility
main
menu,
select
Advanced
Setup
.
d.
Select
Memory
Settings
.
e.
Select
Memory
Mirroring
Settings
.
f.
Enable
the
memory
mirroring
setting
from
within
this
window.
g.
Save
and
exit
the
Configuration/Setup
Utility
program.
When
memory
mirroring
is
enabled,
the
data
that
is
written
to
memory
is
stored
in
two
locations.
One
copy
is
kept
in
the
memory
port
1
DIMMs,
while
a
second
copy
is
kept
in
the
memory
port
2
DIMMs.
During
the
execution
of
the
read
command,
the
data
is
read
from
the
DIMM
with
the
least
number
of
reported
memory
errors
through
memory
scrubbing,
which
is
enabled
with
memory
mirroring.
If
memory
scrubbing
determines
that
a
DIMM
is
damaged
beyond
use,
read
and
write
operations
are
redirected
to
the
remaining
good
DIMMs.
Memory
scrubbing
then
reports
the
damaged
DIMM
and
light
path
diagnostics
displays
the
error.
After
the
damaged
DIMM
is
replaced,
memory
mirroring
then
copies
the
mirrored
data
back
into
the
new
DIMM.
v
Memory
scrubbing
is
an
automatic
daily
test
of
all
the
system
memory
that
detects
and
reports
memory
errors
that
might
be
developing
before
they
cause
a
server
outage.
Note:
Memory
scrubbing
and
Memory
ProteXion
technology
work
with
each
other
and
do
not
require
memory
mirroring
to
be
enabled
to
work.
When
an
error
is
detected,
memory
scrubbing
determines
whether
the
error
is
recoverable.
If
it
is
recoverable,
Memory
ProteXion
is
enabled
and
the
data
that
was
stored
in
the
damaged
locations
is
rewritten
to
a
new
location.
The
error
is
then
reported
so
that
preventive
maintenance
can
be
performed.
Provided
that
there
are
enough
good
locations
to
enable
the
correct
operation
of
the
server,
no
further
action
is
taken
other
than
recording
the
error
in
the
error
logs.
If
the
error
is
not
recoverable,
memory
scrubbing
sends
an
error
message
to
light
path
diagnostics,
which
lights
LEDs
to
guide
you
to
the
damaged
DIMM.
If
memory
mirroring
is
enabled,
the
mirrored
copy
of
the
data
in
the
mirrored
DIMM
is
used
to
refresh
the
new
DIMM
after
it
is
installed.
v
Memory
ProteXion
reassigns
memory
bits
to
new
locations
within
memory
when
recoverable
errors
have
been
detected.
34
IBM
System
x3950
Type
8878
and
System
x3950
E
Type
8879:
User’s
Guide
Summary of Contents for 88743RU - System x3950 E
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