IBM System z10 EC Reference Manual page 39

• Internal Coupling Facility (ICF): Customers considering
clustering technology can get started with Parallel Sysplex
technology at a lower cost by using an ICF instead of
purchasing a standalone Coupling Facility. An ICF feature
is a processor that can only run Coupling Facility Control
Code (CFCC) in a partition. Since CF LPARs on ICFs are
restricted to running only CFCC, there are no IBM software
charges associated with ICFs. ICFs are ideal for Intelligent
Resource Director and resource sharing environments as
well as for data sharing environments where System-Man-
aged CF Structure Duplexing is exploited.
System-Managed CF Structure Duplexing
System-Managed Coupling Facility (CF) Structure Duplex-
ing provides a general purpose, hardware-assisted, easy-
to-exploit mechanism for duplexing CF structure data. This
provides a robust recovery mechanism for failures such as
loss of a single structure or CF or loss of connectivity to a
single CF, through rapid failover to the backup instance of
the duplexed structure pair.
z/OS ICF
z10 EC/z9 EC/z9 BC/z990/z890
A robust failure recovery capability
Note: An example of two systems in a Parallel Sysplex cluster with
CF Duplexing
Parallel Sysplex Coupling Connectivity
The Coupling Facilities communicate with z/OS images
in the Parallel Sysplex environment over specialized
high-speed links. As processor performance increases,
it is important to also use faster links so that link perfor-
mance does not become constrained. The performance,
availability and distance requirements of a Parallel Sysplex
environment are the key factors that will identify the appro-
priate connectivity option for a given configuration.
ICF z/OS
z10 EC/z9 EC/z9 BC/z990/z890
39
When connecting between System z10 EC, System z9
and z990 servers the links must be configured to operate
in Peer Mode. This allows for higher data transfer rates
to and from the Coupling Facilities. The peer link acts
simultaneously as both a CF Sender and CF Receiver link,
reducing the number of links required. Larger and more
data buffers and improved protocols may also improve
long distance performance.
HCA2-C HCA2-C
MBA
HCA2-C
The IBM System z10 EC introduces InfiniBand coupling
link technology designed to provide increased bandwidth
at greater cable distances. At introduction, InfiniBand
coupling links complement and do not replace the current
coupling links (ICB-4, ISC-3) which continue to work in cur-
rent System z and zSeries server environments.
Other advantages of Parallel Sysplex using InfiniBand
(PSIFB):
• InfiniBand coupling links also provide a new ability to
define up to 16 CHPIDs on a single PSIFB port, allow-
ing physical coupling links to be shared by multiple
sysplexes. This also provides additional subchannels for
Coupling Facility communication, improving scalability,
and reducing contention in heavily utilized system con-
figurations. It also allows for one CHPID to be directed
to one CF, and another CHPID directed to another CF on
the same target server, using the same port.
z10 EC
PSIFB 6 GBps
Up to 150 meters
PSIFB 3 GBps
Up to 150 meters
z9 EC, z9 BC
Dedicated CF only
New ICB-4 cable
ICB-4 2 GBps
10 meters
z10 EC, z9 EC, z9 BC, z990, z890
ISC-3
ISC-3
2 Gbps
ISC-3
IFB-MP
ISC-3
ISC-3
Up to 100 Km
I/O Cage
z10 EC, z9 EC, z9 BC, z990, z890