Chapter 10 Usage Scenarios 10-9
Hitachi Universal Replicator for IBM /OS User’s Guide
Disaster Recovery in a 3DC Cascading Configuration
If a disaster or failure occurs in the primary site in a 3DC cascading
configuration, you can use TCz secondary volumes in the intermediate site to
enable the intermediate site to take over your business tasks. If a disaster or
failure occurs in the primary site, first you must transfer your business tasks
from the primary site to the intermediate site.
To transfer your business tasks to the secondary site:
1. Check consistency of the TCz Synchronous R-VOL in the secondary site.
2. Use Business Continuity Manager to execute the YKSUSPND REVERSE
command onto the copy groups that will make a TCz Synchronous pair
between the primary site and the intermediate site.
3. Use the TCz Synchronous R-VOL in the intermediate site to resume your
business tasks.
4. Use Business Continuity Manager to execute the YKRESYNC REVERSE
command onto the copy groups that will make a TCz Synchronous pair
between the primary site and the intermediate site. This operation reverses
the copy direction.
For detailed information about how to use Business Continuity Manager, please
refer to Business Continuity Manager User's Guide.
When a disaster or failure occurs, the above procedure enables you to resume
your business tasks by using TCz Synchronous M-VOLs in the intermediate site.
The TCz Synchronous M-VOLs in the intermediate site will contain the same
data that are stored in the TCz Synchronous M-VOLs in the primary (main) site.
For detailed information about copy status in Business Continuity Manager,
please refer to Business Continuity Manager User's Guide.
Recovering from a Disaster at the Main Site in a 3DC Multi-Target
Configuration
If a disaster or failure occurs only in the primary site in 3DC multi-target
system, you can use secondary volume in the TCz Synchronous secondary site
to enable the secondary site to take over your business tasks. After
transferring your business tasks to the secondary site, you need to remove the
failure from the primary site, so that you will be able to transfer your business
tasks back to the primary site.
To transfer your business tasks to the TCz Synchronous secondary site, follow
the procedure below. Business Continuity Manager is used in this procedure:
1. Use Business Continuity Manager to execute the YKRECVER command on
the journal group corresponding to the URz pair that exists between the
primary and the URz secondary sites.
