HP XP7 Storage - Manual (Page 129)

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If you create more than one delta resync pair, the delta resync P-VOLs in the same master
journal must use the same mirror ID.
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If you plan to create in-system pairs on the remote site sharing the delta resync S-VOL, make
sure to perform the delta resync create-pair operation first, then create in-system pairs.
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You can set a back-up option in the event that the delta resync operation fails. This is done
on the Change Mirror Options window (see the Delta resync Failure step in
“Changing options
used by mirrors ” (page 77) ).
Procedure 40 To create a Continuous Access Journal pair for delta resync pair
1. Install and set up Cnt Ac-S and Cnt Ac-J on the required systems.
2. Create a 3DC multi-target configuration.
1.
Crete a Cnt Ac-S pair from the primary system to the Cnt Ac-S remote site.
2. When the Cnt Ac-S pair’s status is PAIR, create the Cnt Ac-J pair from the primary system
to the Cnt Ac-J remote site.
3. Create a second Cnt Ac-J pair from the Cnt Ac-S S-VOL to the Cnt Ac-J S-VOL. Specify the
Initial Copy option as Delta.
Setting up remote command devices
With remote command devices, communications between each pair of sites is performed
automatically, allowing the delta resync operation to be run.
Two command devices and two remote command devices must be set up on each site: the local
site, the Cnt Ac-S remote site, and the Cnt Ac-J remote site, as shown in
Figure 18 (page 130) .
Also, external paths must be set up on all sites for communications between command devices and
remote command devices.
Procedure 41 To set up remote command devices
1. Set up four command devices each on the local, intermediate, and remote sites.
For more information, see the HP XP7 Provisioning for Open Systems User Guide.
2. Set up and dedicate two external ports and two target ports on each site. Configure paths
between external ports and target ports.
For more information, see HP XP7 External Storage for Open and Mainframe 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:
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Each site should have two command devices mapped via two target ports to the other two
sites.
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Each site should also have two remote command devices mapped-to via external ports from
the other two sites.
The following illustration shows this command/remote command device configuration with port
configuration.
Delta resync configuration 129