storage
unit
that
will
become
the
primary.
That
is,
production
will
failover
to
Site
B
during
this
outage,
which
will
make
the
target
volumes
at
Site
B
convert
to
source
volumes
and
cause
them
to
suspend.
Your
original
source
volumes
at
Site
A
remain
in
the
state
they
were
in
at
the
time
of
the
site
switch.
See
Table
3
for
an
example
of
the
implementation
of
failover
and
failback
operations.
Note:
The
failover
recovery
operation
does
not
reverse
the
direction
of
a
remote
mirror
and
copy
pair.
It
will
change
a
target
volume
into
a
suspended
source
volume,
while
leaving
the
source
volume
in
its
current
state.
The
following
assumptions
are
made
for
this
scenario:
v
Applications
are
updating
the
source
volumes
located
at
Site
A.
v
Paths
are
established
from
Site
A
to
Site
B.
v
Volume
pairs
are
in
duplex
state.
Perform
the
following
steps
using
the
DS
Storage
Manager.
You
can
also
use
the
DS
CLI
to
perform
Copy
Services
functions.
1.
When
the
planned
outage
window
is
reached,
quiesce
applications
to
cease
all
write
I/O
from
updating
the
source
volumes.
Quiescing
your
applications
should
occur
as
part
of
a
planned
outage
and
the
outage
should
be
brief.
Depending
on
the
host
operating
system,
it
might
be
necessary
to
unmount
the
source
volumes.
2.
Perform
a
failover
recovery
operation
to
Site
B.
After
the
failover
operation
has
processed
successfully,
the
volumes
at
Site
B
transition
from
target
to
source
volumes.
3.
Depending
on
your
path
design
and
when
the
source
storage
unit
becomes
available,
create
paths
in
the
opposite
direction
from
Site
B
to
Site
A.
You
will
need
the
paths
in
the
opposite
direction
if
you
want
to
transfer
the
updates
back
to
Site
A.
4.
Depending
on
your
operating
system,
it
might
be
necessary
to
rescan
your
fibre-channel
connected
devices
(to
remove
device
objects
for
the
site
A
volumes
and
recognize
the
new
source
volumes).
5.
Mount
your
target
volumes
(now
the
new
source
volumes)
on
the
target
storage
unit
at
Site
B.
6.
Start
all
applications.
After
the
applications
start,
all
write
I/O
operations
to
the
source
volumes
are
tracked.
Depending
on
your
plans
regarding
Site
A,
the
volume
pairs
can
remain
suspended
(if
you
want
to
do
offline
maintenance).
7.
When
your
scheduled
maintenance
is
complete,
schedule
a
time
for
a
failback
recovery
operation
to
initiate
the
transfer
of
data
back
to
Site
A.
This
process
resynchronizes
the
volumes
at
Site
A
with
the
volumes
at
Site
B.
Note:
Failback
recovery
operations
are
usually
used
after
a
failover
recovery
has
been
issued
to
restart
mirroring
either
in
the
reverse
direction
(remote
site
to
local
site)
or
original
direction
(local
site
to
remote
site).
Table
3.
Failover
and
failback
implementation
Step
Operation
Manage-
ment
required
to
Format
of
source
volume
and
target
volume
Format
of
source
and
target
volume
pair
Result:
Site
A
Result:
Site
B
1
142
DS8000
User’s
Guide
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
||
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
Summary of Contents for TotalStorage DS8000
Page 1: ...IBM TotalStorage DS8000 User s Guide SC26 7623 03...
Page 2: ......
Page 3: ...IBM TotalStorage DS8000 User s Guide SC26 7623 03...
Page 10: ...viii DS8000 User s Guide...
Page 12: ...x DS8000 User s Guide...
Page 14: ...xii DS8000 User s Guide...
Page 24: ...Department 61C 9032 South Rita Road TUCSON AZ 85775 4401 xxii DS8000 User s Guide...
Page 26: ...xxiv DS8000 User s Guide...
Page 50: ...24 DS8000 User s Guide...
Page 116: ...90 DS8000 User s Guide...
Page 120: ...94 DS8000 User s Guide...
Page 152: ...126 DS8000 User s Guide...
Page 166: ...140 DS8000 User s Guide...
Page 184: ...158 DS8000 User s Guide...
Page 186: ...160 DS8000 User s Guide...
Page 192: ...Taiwan class A compliance statement VS07171L 166 DS8000 User s Guide...
Page 227: ......
Page 228: ...Printed in USA SC26 7623 03...
