HP XP P9500 Storage - Manual (Page 34)

Establishing connections between multiple secondary systems
When using more than one primary system and more than one secondary system, connections
among the secondary systems must be established by configuring paths and ports.
To configure ports and paths between secondary systems
1.
Create a command device in each of the secondary systems.
2. Configure external ports on the secondary system to be used as the supervisor DKC.
3. Configure paths between the external ports and the target ports on the systems to be used as
subordinate DKCs. In the example in
Figure 5 (page 34) , the secondary system 1 has external
ports, each of which is connected with a target port on the secondary systems 2 and 3. For
more information about external ports, see HP StorageWorks P9000 External Storage for
Open and Mainframe Systems User Guide. For details on configuring paths, see HP
StorageWorks P9000 Provisioning for Open Systems User Guide.
4. Create mapping between command devices in the supervisor DKC and the subordinate DKCs.
Figure 5 (page 34) shows an example. The supervisor DKC must be able to use command
devices in subordinate DKCs via remote command devices.
In the example, command devices A and B are created in secondary systems 2 and 3. Remote
command devices are created in the secondary system 1 (the supervisor DKC), and are mapped
to subordinate DKCs. The emulation type of command devices and remote command devices
must be OPEN-V. For more information about remote command devices, see HP StorageWorks
P9000 External Storage for Open and Mainframe Systems User Guide.
Figure 5 Connections between Supervisor, Subordinate DKCs
By using Fibre Channel switches, target ports can also be connected to RCU target ports on the
secondary systems. See
“Planning ports for data transfer ” (page 43) for more information.
CAUTION: Performing maintenance operations on remote command devices (for example, the
devices A' and B' in above figure) used for connections between secondary systems cause the
pairs to be suspended as if a failure had occurred. To avoid this, before performing maintenance
tasks, remove all journals in the extended consistency group that use the remote command devices
under maintenance.
Planning extended consistency groups (EXCTG)
An EXCTG is a collection of journals in which data consistency is guaranteed. You register journals
in an EXCTG when performing copy operations between multiple primary systems and multiple
secondary systems. See
“Using extended consistency groups” (page 47) for planning and set up
information.
34 Planning volumes, systems