3-22 Chapter 3 Preparing for Universal Replicator z/OS Operations
Hitachi Universal Replicator for IBM /OS User’s Guide
Configuring Paths and Ports to Establish Connections among Secondary
Storage Systems
To establish connections among secondary storage systems, you must
configure external ports on the storage system that should be used as the
supervisor DKC. After that, you must configure paths between these external
ports and the target ports on the storage systems that should be used as
subordinate DKCs. In the example in
Figure 3-7, the secondary storage
system 1 has external ports, each of which is connected with a target port on
the secondary storage system 2 and 3. For details on external ports, please
refer to the Universal Volume Manager User's Guide. For details on configuring
paths, please refer to the LUN Manager User's Guide.
By using fibre channel switches, target ports can also be connected to RCU
target ports on secondary storage systems. For details on RCU target ports,
see section
Initiator Ports and RCU Target Ports. For details on configuring
ports, see section
Configuring Port Attributes.
Creating Remote Command Devices to Establish Connections among
Secondary Storage Systems
To establish connections among secondary storage systems, first you must
create a command device in each of the secondary storage systems. Next you
must create mapping between command devices in the supervisor DKC and
the subordinate DKCs. Thus, the supervisor DKC will be able to use command
devices in subordinate DKCs via remote command devices.
In the example of
Figure 3-7, the command devices A and B are created in the
secondary storage systems 2 and 3. Also, remote command devices are
created in the secondary storage system 1 (i.e., the supervisor DKC), and are
mapped to the secondary storage systems 2 and 3 (i.e., subordinate DKCs).
The emulation type of command devices and remote command devices must
be OPEN-V. For details on remote command devices, please refer to the
Universal Volume Manager User's Guide.
Caution: If maintenance operations are performed on remote command
devices (for example, the devices A' and B' in
Figure 3-7) that are used for
connections among secondary storage systems, the pair will be suspended
according to a failure. To avoid this, you must remove all journal groups in the
extended consistency group that uses the remote command devices to be
maintained.
