Access (3dc cascading configuration), Combining xp continuous access – HP XP Continuous Access Software User Manual
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Figure 27 Restoring XP Business Copy P-VOLs, step 8
9.
Execute the XP RAID Manager
pairresync
command on the XP Continuous Access Journal
pair to resynchronize the pair.
Figure 28 Restoring XP Business Copy P-VOLs, step 9
Combining XP Continuous Access Journal with XP Continuous Access (3DC cascading
configuration)
The local array allows XP Continuous Access Journal and XP Continuous Access Synchronous to
be combined. This combination is intended to ensure that the response time against host I/Os is
comparable, regardless of whether the distance between the primary and secondary sites is short
or long. This combination is also intended to ensure that the secondary site stores data that has
been stored in the primary site even if a failure occurs in the primary site. These intentions are
fulfilled if remote copy operations are performed using cascading connections and a three data
center (3DC) configuration. In a 3DC configuration, an intermediate site is located between the
primary and secondary sites.
shows an example of a 3DC cascading configuration in which XP Continuous
Access Journal and XP Continuous Access Synchronous are combined. In this configuration, the
volume in the primary site is an XP Continuous Access Synchronous primary volume (P-VOL). The
corresponding XP Continuous Access secondary volume (S-VOL) is the volume in the intermediate
site, which is a short distance from the primary site. This XP Continuous Access Synchronous
secondary volume is also used as an XP Continuous Access Journal primary data volume. The
corresponding XP Continuous Access Journal secondary data volume is the volume in the secondary
site, which is a long distance from the intermediate site. If a host issues an I/O to the XP Continuous
Access Synchronous primary volume in the primary site, data is transferred using XP Continuous
Access Synchronous and XP Continuous Access Journal to the secondary site and is restored to
the secondary data volume.
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XP Continuous Access Journal operations requirements and restrictions