Specifications

Mixed configuration
Figure 41 on page 74 shows another example of a S/390 or zSeries host system
with four ESCON channels 1. In this example, two FICON channels 2 have
been added to an S/390 or zSeries host. The illustration also shows the
channel-path group 3 and FICON directors 4 through which the two FICON
adapters 5 are installed in the ESS.
The two FICON directors 4 are not required. You can improve reliability by
eliminating a single point of failure. The sngle point of failure might be present if
both FICON channels 2 are connected to a single FICON director. You can
connect the FICON channels 2 to the ESS FICON adapters 5 directly, without
directors.
Figure 41 on page 74 also shows four ESCON adapters 6 and two ESCON
directors 7. This configuration gives you the most flexibility for future I/O changes.
Figure 41 on page 74 illustrates the FICON channels 2 that have been added to
the existing ESCON channel-path group 3. Because the channel-path group has
ESCON and FICON channel paths, it makes migrating easier. This intermixing of
types of channel-paths allows you to nondisruptively add FICON channels 2 to
the host and to add FICON adapters 5 to the ESS.
Notes:
1. The configuration in Figure 41 on page 74 is supported for migration only.
2. Do not use this configuration for an extended period.
3. IBM recommends that you migrate from a mixed channel-path group
configuration to an all FICON channel-path group configuration.
S/390 or
zSeries Host
1
2
4 4 4 4
ESS
1 1 1
3 3
S009064
Figure 40. Example of an ESCON configuration
Chapter 7. Attaching to an IBM S/390 or IBM eServer zSeries host 73