HP XP Continuous Access Software - Manual (Page 27)

creating XP Continuous Access Journal pairs for delta resync operations, see Requirements for
creating XP Continuous Access Journal pairs for delta resync operations .
For information about the delta resync operation that is performed when a failure occurs in the
configuration shown in
Figure 7 (page 26) , see Switching XP'sContinuous Accessmaster journal
group . The contingency XP Continuous Access Journal pair must be in HOLD status when the failure
occurs in order to perform a delta resync operation. However, the contingency XP Continuous
Access Journal pair status can be changed to HLDE, for example, when a cache memory or shared
memory error occurs at the DC2 XP Continuous Access Synchronous secondary site or when you
cannot obtain a journal at the XP Continuous Access Synchronous secondary site because the
master journal volume failed or a pinned track occurred. If the status of the contingency XP
Continuous Access Journal pair for a delta resync operation changes to HLDE due to one of the
conditions described above, follow the steps in
Restoring a pair of data volumes and change the
pair status back to HOLD again.
Switching XP's Continuous Access master journal group
When a failure occurs on the DC1 primary site in Figure 7 (page 26) the DC2-to-DC3 XP Continuous
Access Journal pair can then use the contingency journal group in the XP Continuous Access
Synchronous secondary site as the new master journal group. To switch the master journal group,
first change the XP Continuous Access Synchronous secondary site to a primary site using XP's
RAID Manager
horctakeover command, and then perform a delta resync operation on the
primary data volume of the contingency XP Continuous Access Journal pair that was in HOLD status
to activate data flow for that logical connection.
Figure 8 (page 27) shows an example.
Figure 8 Delta resync activation in a 3DC multi-target configuration (after failure occurs)
In Figure 8 (page 27) , because a failure occurs in primary site A (DC1), the horctakeover
command is used at DC2 to change the former XP Continuous Access Synchronous secondary site
(DC2) to be the primary site. If you perform a DC2-to-DC3 delta resync operation in this situation,
XP Continuous Access Journal delta resync operations 27