Configuring Delta Resync Operation Environment To Support Remote Command Devices; Establish Immediate Communications - HP StorageWorks P9000 User Manual

2. Create a Continuous Access Synchronous Z pair on the primary system, following the
information in the following sections:
"Prerequisite information for 3DC multitarget" (page 136)
"Prerequisite information for creating the delta resync pair" (page 138)
3. After the Continuous Access Synchronous Z pair status is Duplex, create the Continuous Access
Journal Z pair on the primary system, following the information in the following sections:
"Prerequisite information for 3DC multitarget" (page 136)
"Prerequisite information for creating the delta resync pair" (page 138)
4. Create a second Continuous Access Journal Z pair from the Continuous Access Synchronous
Z R-VOL to the Continuous Access Journal Z S-VOL. Specify the Initial Copy option as Delta.

Configuring delta resync operation environment to support remote command devices

The delta resync operation is executed using the Resume Pair operation. Please review the
prerequisites for the delta resync operation in
Review the following information regarding an update requirement for the delta resync operation,
and a workaround using remote command devices.

Establish immediate communications

When the delta resync operation has been performed and pair status is changed to PAIR, the delta
resync P-VOL must be updated from the host for longer than five minutes. This is required to insure
internal communications between the intermediate and remote sites.
However, you can work around this five-minute-plus update requirement by setting up command
devices and remote command devices. With remote command devices set up, communications
between the two sites is performed automatically, and the delta resync is ready to go when the
operation is executed.
This requires setting up two command devices and two remote command devices on each site —
the local, intermediate, and remote sites — as explained in the following general guidelines.
Consult the HP StorageWorks P9000 External Storage for Open and Mainframe Systems User
Guide for more complete information about remote command devices.
1. Setup four command devices each on the local, intermediate, and remote sites.
2. Set up and dedicate two external ports and two target ports on each site for the
command/remote command devices. Configure paths between external ports and target ports.
For detail about the external ports, see HP StorageWorks P9000 External Storage for Open
and Mainframe Systems User Guide. For instruction on setting paths, see HP StorageWorks
P9000 Provisioning for Open Systems User Guide.
3. On each site, map a command device via a target port to a device on one of the other sites.
The device on the other site should be mapped to as a remote command device, using an
external port on that system.
4. Repeat the previous step so that two command devices on each site are mapped to a remote
command device on each of the other two sites.
Thus:
Each site should have two command devices mapped via two target ports to the other two
sites.
Each site should also have two remote command devices mapped to via external ports from
the other two sites.
An illustration follows of this command/remote command device configuration.
140 Continuous Access Journal Z configurations with Continuous Access Synchronous Z
"Restore a pair" (page 74).