
Periodically,
the
incremental
resynchronization
function
performs
queries
from
each
of
the
A
volumes
at
the
local
site
to
each
of
the
B
volumes
at
the
intermediate
site
to
determine
when
data
has
been
secured
on
the
C
volumes
at
the
remote
site.
The
queries
generate
a
report
that
allows
you
to
view
the
following
types
of
information:
v
How
often
consistency
groups
are
being
formed
in
the
Global
Mirror
environment
v
The
number
of
successful
consistency
groups
that
have
formed
since
the
last
query
In
addition
to
the
periodic
queries,
you
can
issue
a
query
from
the
DS
CLI
command
prompt
using
the
showgmir
-metrics
command.
This
command
generates
a
report
that
displays
the
status
of
consistency
group
formation.
If
the
Metro
Mirror
volume
pairs
are
in
full
duplex
status
and
at
least
three
consistency
groups
have
formed
successfully,
then
data
from
the
local
site
volumes
is
secure
on
the
remote
site
volumes.
The
incremental
resynchronization
function
uses
a
mechanism
to
determine
how
often
and
how
many
tracks
must
change
on
the
specified
primary
volumes
before
it
resets
(and
clears)
the
bitmaps
after
in
flight
data
is
secured
on
the
remote
site
volumes.
This
process
continues
until
you
disable
the
incremental
resynchronization
function
on
the
primary
volumes
using
the
mkpprc
command
or
the
primary
Metro
Mirror
volumes
become
secondary
volumes.
If
you
started
the
incremental
resynchronization
function
with
initialization
and
an
outage
occurs
at
the
intermediate
site,
you
can
restart
a
recovery
configuration
with
Global
Mirror
running
between
the
local
and
remote
sites.
Starting
the
incremental
resynchronization
function
without
initialization
Starting
incremental
resynchronization
without
initialization
means
that
the
change
recording
bitmaps
are
created
but
started
with
all
zeros
on
the
primary
Metro
Mirror
volumes.
Do
not
specify
the
incremental
resynchronization
function
without
initialization
except
in
some
specific
recovery
scenarios.
Recovering
with
the
incremental
resynchronization
function
In
an
existing
Metro/Global
Mirror
configuration,
if
the
intermediate
site
fails,
use
the
mkpprc
command
with
the
-incrementalresync
recover
parameter
to
restart
your
disaster
recovery
environment.
This
initiates
the
processing
of
Global
Mirror
between
the
local
and
remote
sites.
Before
the
mkpprc
command
completes
its
process,
the
system
verifies
that
the
specified
volumes
have
the
intermediate
volumes
in
common.
This
verification
ensures
that
the
primary
volume
specified
in
the
command
is
the
Metro
Mirror
A
volume
and
the
secondary
volume
specified
is
the
Global
Copy
C
volume
of
a
Metro/Global
Mirror
configuration.
When
the
mkpprc
command
processes,
only
changes
on
the
A
volumes
that
have
the
change
recording
mechanism
started
are
copied
to
the
C
volumes
at
the
remote
site.
A
full
volume
copy
of
these
volumes
is
not
required.
128
DS8000
User’s
Guide
Содержание DS8000 - ADDITIONAL INFORMATION
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