Filter
Top Products
44
Parallel Sysplex Coupling Connectivity
The Coupling Facilities communicate with z/OS images
in the Parallel Sysplex environment over specialized
high-speed links. For availability purposes, it is recom-
mended that there be at least two links connecting each
z/OS image to each CF in a Parallel Sysplex cluster. As
processor performance increases, it is important to also
use faster links so that link performance does not become
constrained. The performance, availability and distance
requirements of a Parallel Sysplex environment are the key
factors that will identify the appropriate connectivity option
for a given confi guration.
Parallel Sysplex Coupling Links on the zSeries have been
enhanced with the introduction of Peer Mode. When con-
necting between zSeries servers, the links can be confi g-
ured to operate in Peer Mode. This allows for higher data
transfer rates to and from the Coupling Facilities. In Peer
Mode, the fi ber optic single mode coupling link (ISC-3)
provides 200 Gbps capacity, up to 12 km, 100 Gbps up
to 20 km, the ICB-3 link with 1 GB/s peak capacity, the
ICB-4 supported on z890s and z990s connection at 2.0
GBps, and the IC-3 link with 3.5 GBps capacity. Additional
Peer Mode benefi ts are obtained by enabling the link to
be MIFed between z/OS (or OS/390) and CF LPARs. 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
also improve long distance performance. For connectiv-
ity to 9672s, zSeries ISC-3 CF links can be confi gured to
run in Compatibility Mode with the same characteristics
as links on the 9672 of 100 Gbps. The ICB coupling link
speeds described above are theoretical maximums. Note:
The z890 does not support ICB-2 links for connectivity to
9672s. ISC-3 links in compatibility mode must be used.
GDPS/PPRC Cross Site Parallel Sysplex distance Extended to
100 km
When using a Dense Wave Division Multiplexer (DWDM),
it will be possible via an RPQ to confi gure GDPS/PPRC or
a multi-site Parallel Sysplex with up to 100 km between
the two sites. The immediate advantage of this extended
distance is to potentially decrease the risk that the same
disaster will affect both sites, thus providing the ability
for customers to recover their production applications at
another site. Support for the External Timer Reference
(ETR) links and the Inter System Channel (ISC-3) links
has been increased from the current capability of 50 km
to an extended capability of up to 100 km. The extended
distance support for ETR and ISC-3 links is now consis-
tent with other cross site technologies that already sup-
port 100 km (such as FICON, Peer-to-Peer Remote Copy
(PPRC), and Peer-to-Peer Virtual Tape Server (PtP VTS)).
It should be noted that the maximum distance between a
pair of 9037 Sysplex Timers in an Expanded Availability
confi guration remains at 40 km. Therefore, to achieve the
extended distance of 100 km between the two sites, one of
the options to be considered is locating one of the Sysplex
Timers in an intermediary site that is less than 40 km
from one of the two sites (as can be seen in the diagram
below). Other potential options can be evaluated when the
RPQ is ordered.
CPC CPC
D
W
D
M
D
W
D
M
D
W
D
M
D
W
D
M
D
W
D
M
D
W
D
M
Route A
Route B
ETR
ETR
ETR
ETR
ETR
ETR
ETR
CLO
CLO
1
12
2
3
4
5
6
7
8
9
10
11
1
12
2
3
4
5
6
7
8
9
10
11
9037
9037
1ETRlink
perCPC
hutwith
amplifiers
1ETR
linkper
CPC
1ETR
linkper
CPC
2CLO
links
40 kmmax 40km nom
up to
100 km
Site 1 Site 2
Note: Midspan9037 can alsobe located within 40km of site 2or on Route B.
All ETR andCLO links are provisioned as1 channel per wavelength.