<s>
IBM	B-Operating_System
PowerHA	I-Operating_System
SystemMirror	I-Operating_System
(	O
formerly	O
IBM	O
PowerHA	O
and	O
HACMP	B-Operating_System
)	O
is	O
IBM	O
's	O
solution	O
for	O
high-availability	B-General_Concept
clusters	I-General_Concept
on	O
the	O
AIX	B-Application
Unix	B-Application
and	O
Linux	B-Application
for	O
IBM	B-Device
System	I-Device
p	I-Device
platforms	O
and	O
stands	O
for	O
High	B-Operating_System
Availability	I-Operating_System
Cluster	I-Operating_System
Multiprocessing	I-Operating_System
.	O
</s>
<s>
IBM	O
's	O
HACMP	B-Operating_System
product	O
was	O
first	O
shipped	O
in	O
1991	O
and	O
is	O
now	O
in	O
its	O
20th	O
release	O
-	O
PowerHA	O
SystemMirror	O
for	O
AIX	B-Application
7.1	O
.	O
</s>
<s>
Data	O
on	O
file	B-Application
systems	I-Application
can	O
be	O
shared	O
between	O
systems	O
in	O
the	O
cluster	O
.	O
</s>
<s>
PowerHA	O
relies	O
heavily	O
on	O
IBM	O
's	O
Reliable	B-Operating_System
Scalable	I-Operating_System
Cluster	I-Operating_System
Technology	I-Operating_System
(	O
RSCT	B-Operating_System
)	O
.	O
</s>
<s>
PowerHA	O
is	O
an	O
RSCT	B-Operating_System
aware	O
client	O
.	O
</s>
<s>
RSCT	B-Operating_System
is	O
distributed	O
with	O
AIX	B-Application
.	O
</s>
<s>
RSCT	B-Operating_System
includes	O
a	O
daemon	O
called	O
group	O
services	O
that	O
coordinates	O
the	O
response	O
to	O
events	O
of	O
interest	O
to	O
the	O
cluster	O
(	O
for	O
example	O
,	O
an	O
interface	O
or	O
a	O
node	O
fails	O
,	O
or	O
an	O
administrator	O
makes	O
a	O
change	O
to	O
the	O
cluster	O
configuration	O
)	O
.	O
</s>
<s>
Up	O
until	O
PowerHA	O
V6.1	O
,	O
RSCT	B-Operating_System
also	O
monitored	O
cluster	O
nodes	O
,	O
networks	O
and	O
network	O
adapters	O
for	O
failures	O
using	O
the	O
topology	O
services	O
daemon	O
(	O
topsvcs	O
)	O
.	O
</s>
<s>
In	O
the	O
current	O
release	O
(	O
V7.1	O
)	O
,	O
RSCT	B-Operating_System
provides	O
coordinate	O
response	O
between	O
nodes	O
,	O
but	O
monitoring	O
and	O
communication	O
are	O
provided	O
by	O
the	O
Cluster	O
Aware	O
AIX	B-Application
(	O
CAA	O
)	O
infrastructure	O
.	O
</s>
<s>
The	O
7.1	O
release	O
of	O
PowerHA	O
relies	O
heavily	O
on	O
CAA	O
,	O
a	O
clustering	O
infrastructure	O
built	O
into	O
the	O
operating	O
system	O
and	O
exploited	O
by	O
RSCT	B-Operating_System
and	O
PowerHA	O
.	O
</s>
<s>
CAA	O
provides	O
the	O
monitoring	O
and	O
communication	O
infrastructure	O
for	O
PowerHA	O
and	O
other	O
clustering	O
solutions	O
on	O
AIX	B-Application
,	O
as	O
well	O
as	O
cluster-wide	O
event	O
notification	O
using	O
the	O
Autonomic	O
Health	O
Advisor	O
File	B-Application
System	I-Application
(	O
AHAFS	O
)	O
and	O
cluster-aware	O
AIX	B-Application
commands	O
with	O
clcmd	O
.	O
</s>
<s>
CAA	O
replaces	O
the	O
function	O
provided	O
by	O
Topology	O
Services	O
(	O
topsvcs	O
)	O
in	O
RSCT	B-Operating_System
in	O
previous	O
releases	O
of	O
PowerHA/HACMP	O
.	O
</s>
<s>
PowerHA	O
6.1	O
,	O
Rebranded	O
again	O
to	O
IBM	B-Operating_System
PowerHA	I-Operating_System
SystemMirror	I-Operating_System
for	O
AIX	B-Application
,	O
GA	O
Oct	O
27	O
2009	O
,	O
</s>
<s>
HACMP	B-Operating_System
5.5	O
,	O
Rebranded	O
to	O
IBM	O
PowerHA	O
,	O
GA	O
Nov	O
2008	O
,	O
</s>
<s>
HACMP	B-Operating_System
5.4.1	O
,	O
Nov	O
2007	O
,	O
</s>
<s>
HACMP	B-Operating_System
5.4	O
,	O
July	O
2006	O
,	O
</s>
