HP StorageWorks XP Remote Web Console Software - Manual (Page 79)

will also be written to the URz secondary data volume, asynchronously with writing from the host.
Update sequence consistency will be maintained with the URz secondary data volume.
Since writing from the URz primary volume to the URz secondary volume is performed
asynchronously with writing from the host to the primary volume, this configuration can prevent
delay in response to the host even if the URz primary site and the URz secondary site are far from
each other.
In addition, you can create the URz pair for delta resync operation in 3DC multi-target configuration,
by specifying TCz Synchronous R-VOL in the TCz Synchronous secondary site as the URz primary
data volume, and by specifying the volume in the URz secondary site as the URz secondary data
volume. If you create the URz pair for delta resync operation, you can resynchronize the URz pair
by using journal data in the TCz Synchronous secondary site when a failure occurs in the primary
site.
For detailed information about the hardware configuration required for 3DC multi-target
configuration, see
“Hardware Configuration” (page 79) . For detailed information about the
requirements to create a URz pair for delta resync operation, see “Requirements for Creating URz
Pair for Delta Resync Operation” (page 81) . As for the requirements to perform delta resync
operation, see “Requirements for Performing Delta Resync Operation” (page 81) .
If a failure occurs in a TCz Synchronous primary volume, which is also used as a URz primary
data volume, you can resume business tasks by using the TCz Synchronous secondary volume.
After you resume business tasks, you need to remove the failure from the primary volume and
transfer business tasks back to the primary site. For details, see
“Recovering from Failures in the
Primary Site and the TCz Synchronous Secondary Site” (page 90) through “Transferring Business
Tasks from the URz Secondary Site to the Primary Site” (page 91) .
If a failure occurs in both the primary volume and the TCz Synchronous secondary volume, you
can resume your business tasks by using the URz secondary data volume. After you resume business
tasks, you need to remove the failure from the primary volume and the TCz Synchronous secondary
volume, and transfer business tasks back to the primary site.
Hardware Configuration
A computer system in 3DC multi-target configuration requires the following three sites:
•
Primary site for both TCz Synchronous and URz
•
Secondary site for TCz Synchronous
•
Secondary site for URz
Each of these sites requires one XP storage system and XP Remote Web Console computers. It is
recommended that Business Continuity Manager should be installed in host computers in each of
these sites.
The following list explains hardware configuration for XP storage systems in these sites.
•
XP storage system in the primary site:
The XP storage system must have TCz Synchronous installed. ◦
◦ The XP storage system must have URz installed.
◦ The XP storage system must have a volume used as a TCz Synchronous primary volume
and a URz primary data volume.
Combining URz with Other Data Management Operations 79