HP StorageWorks XP Remote Web Console Software - Manual (Page 62)

Figure 19 An Example of Connections among Secondary Subsystems
Based on the example in Figure 19 (page 62) , the subsections below explain configuration of
paths and ports, and creation of remote command devices.
Configuring paths and Ports to Establish Connections among Secondary Storage Systems
To establish connections among secondary subsystems, you must configure external ports on the
subsystem that should be used as the supervisor DKC. After that, you must configure paths between
these external ports and the target ports on the subsystems that should be used as subordinate
DKCs. In the example in
Figure 19 (page 62) , the secondary subsystem 1 has external ports, each
of which is connected with a target port on the secondary subsystem 2 and 3. For details on
external ports, see the HP StorageWorks XP External Storage user guide for XP12000/XP10000
Disk Arrays and SVS 200. For details on configuring paths, see the HP StorageWorks XP LUN
Configuration and Security Manager User Guide for XP12000/XP10000 Disk Arrays and SVS
200: LUN Manager and Volume Manager.
By using fibre channel switches, target ports can also be connected to RCU target ports on secondary
subsystems. For details on RCU target ports, see
Initiator Ports and RCU Target Ports . For details
on configuring ports, see “Configuring Port Attributes” (page 99) .
Creating Remote Command Devices to Establish Connections among Secondary Storage Systems
To establish connections among secondary subsystems, first you must create a command device
in each of the secondary subsystems. 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 19 (page 62) , the command devices A and B are created in the secondary
subsystems 2 and 3. Also, remote command devices are created in the secondary subsystem 1
(that is, the supervisor DKC), and are mapped to the secondary subsystems 2 and 3 (that is,
subordinate DKCs).
The emulation type of command devices and remote command devices must be OPEN-V. For
details on remote command devices, see the HP StorageWorks XP External Storage user guide for
XP12000/XP10000 Disk Arrays and SVS 200.
CAUTION: If maintenance operations are performed on remote command devices that are used
for connections among secondary subsystems, 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.
Disaster Recovery for Multiple Primary and Secondary Storage Systems
Consistency of Data Update Sequence When a Disaster Occurs
When a failure occurs in some primary or secondary storage system, all journal groups in the
extended consistency group will be suspended and remote copy operations will be suspended.
62 Requirements and Restrictions for Universal Replicator z/OS Operations