<s>
Global	B-Application
Mirror	I-Application
is	O
an	O
IBM	O
technology	O
that	O
provides	O
data	B-Architecture
replication	I-Architecture
over	O
extended	O
distances	O
between	O
two	O
sites	O
for	O
business	O
continuity	O
and	O
disaster	B-General_Concept
recovery	I-General_Concept
.	O
</s>
<s>
If	O
adequate	O
bandwidth	O
exists	O
,	O
Global	B-Application
Mirror	I-Application
provides	O
a	O
recovery	O
point	O
objective	O
(	O
RPO	O
)	O
of	O
as	O
low	O
as	O
3	O
–	O
5	O
seconds	O
between	O
the	O
two	O
sites	O
at	O
extended	O
distances	O
with	O
no	O
performance	O
impact	O
on	O
the	O
application	O
at	O
the	O
primary	O
site	O
.	O
</s>
<s>
The	O
two	O
sites	O
can	O
be	O
on	O
separate	O
continents	O
or	O
simply	O
on	O
different	O
utility	B-Architecture
grids	I-Architecture
.	O
</s>
<s>
IBM	O
also	O
provides	O
a	O
synchronous	O
data	B-Architecture
replication	I-Architecture
called	O
Metro	B-Device
Mirror	I-Device
,	O
which	O
is	O
designed	O
to	O
support	O
replication	B-Architecture
at	O
"	O
Metropolitan	O
"	O
distances	O
of	O
(	O
normally	O
)	O
less	O
than	O
300km	O
.	O
</s>
<s>
Global	B-Application
Mirror	I-Application
is	O
based	O
on	O
IBM	O
Copy	O
Services	O
functions	O
:	O
Global	O
Copy	O
and	O
FlashCopy	B-Device
.	O
</s>
<s>
Global	B-Application
mirror	I-Application
periodically	O
pauses	O
updates	O
of	O
the	O
primary	O
volumes	O
and	O
swaps	O
change	O
recording	O
bitmaps	O
.	O
</s>
<s>
After	O
all	O
primary	O
updates	O
have	O
been	O
drained	O
,	O
the	O
secondary	O
volumes	O
are	O
used	O
as	O
the	O
source	O
for	O
a	O
FlashCopy	B-Device
to	O
tertiary	O
volumes	O
at	O
the	O
recovery	O
site	O
.	O
</s>
<s>
By	O
grouping	O
many	O
volumes	O
into	O
one	O
Global	B-Application
Mirror	I-Application
session	O
multiple	O
volumes	O
may	O
be	O
copied	O
to	O
the	O
recovery	O
site	O
simultaneously	O
while	O
maintaining	O
point-in-time	O
consistency	O
across	O
those	O
volumes	O
.	O
</s>
<s>
Global	B-Application
Mirror	I-Application
can	O
be	O
combined	O
with	O
a	O
wide	O
area	O
network	O
clustering	O
product	O
like	O
Geographically	O
Dispersed	O
Parallel	O
Sysplex	O
(	O
GDPS	O
)	O
,	O
HACMP/XD	O
,	O
or	O
IBM	O
TotalStorage	B-Application
Continuous	O
Availability	O
for	O
Windows	O
to	O
provide	O
for	O
automated	O
failover	O
between	O
sites	O
.	O
</s>
<s>
The	O
Global	B-Application
Mirror	I-Application
function	O
is	O
available	O
on	O
IBM	B-Application
Storage	I-Application
devices	O
including	O
the	O
DS8000	B-Device
series	I-Device
(	O
DS8100	O
,	O
DS8300	O
,	O
DS8700	O
,	O
DS8800	O
,	O
DS8870	O
)	O
,	O
the	O
DS6800	O
,	O
the	O
Enterprise	B-Device
Storage	I-Device
Server	I-Device
Models	O
800	O
and	O
750	O
,	O
midrange	O
storage	O
servers	O
V7000	O
,	O
DS4000	O
family	O
,	O
and	O
the	O
IBM	B-Application
SAN	I-Application
Volume	I-Application
Controller	I-Application
.	O
</s>
