
11.5.1 Connect to zSeries hosts
Figure 11-11 displays a configuration fragment on how to connect a DS6800 to a FICON host.
blue I/O
preferred path | preferred path |
red I/O | blue I/O |
red I/O
Server 0
blue |
Server enclosure
Server 1
red |
Fibre Channel switch |
ooo |
16 DDM |
Fibre Channel switch |
Fibre Channel switch |
ooo |
16 DDM |
Fibre Channel switch |
Expansion enclosure
Figure 11-11 DS6800 front end connectivity example - partial view
The physical connectivity does not reveal what is important to consider when creating logical volumes and assigning these volumes to LCUs. Before considering different configuration approaches, we provide some general discussion on the potential of the DS6000 series in the following sections.
11.5.2 Performance potential in z/OS environments
FICON channels started in the IBM 9672 G5 and G6 servers with 1 Gbps. Eventually these channels were enhanced to FICON Express channels in IBM 2064 and 2066 servers, with double the speed, so they now operate at 2 Gbps.
The DS6000 series provides only 2 Gbps FCP ports, which can be configured either as FICON to connect to zSeries servers or as FCP ports to connect to Fibre
I/O rates with 4 KB blocks are in the range of 6,800 I/Os per second or more per FICON Express channel, again a conservative number. A single FICON Express channel can actually perform up to about 9,000 read hit I/Os per second on the DS8000. This particular example in Figure
234DS6000 Series: Concepts and Architecture