HP StorageWorks XP Remote Web Console Software - Manual (Page 178)

7 Using Extended Consistency Groups
This chapter explains how to perform remote copy operations between more than one primary
and secondary storage system, as well as how to register journal groups in extended consistency
groups (abbreviated as EXCTGs).
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“Registering Journal Groups in an Extended Consistency Group” (page 178)
•
“Manipulating Data Volume Pairs in Extended Consistency Groups” (page 181)
•
“Removing Journal Groups from an Extended Consistency Group” (page 182)
•
“Forcibly Removing Journal Groups from an Extended Consistency Group” (page 184)
To perform remote copy operations between more than one primary storage system and more than
one secondary storage system, you must register journal groups in extended consistency groups
(abbreviated as EXCTGs). To register journal groups in extended consistency groups, use the
EXCTG Operation window.
•
Displaying the EXCTG Operation window (see “EXCTG Operation Window” (page 129) )
•
Registering journal volumes in an extended consistency group (see the next section)
•
Removing journal volumes from an extended consistency group (see “Removing Journal Groups
from an Extended Consistency Group” (page 182) )
Registering Journal Groups in an Extended Consistency Group
To perform remote copy operations between more than one primary storage system and more than
one secondary storage system, you must register journal groups in an extended consistency group,
which is abbreviated as EXCTG.
•
Notes on configuring an extended consistency group:
Confirm that the journal groups to be registered are in Active or Stop status. This means
that you must have at least one pair active or suspended in each JNLG to be registered
in the EXCTG in each disk array. ◦
◦ Do not register master and restore journal groups in the same extended consistency group.
◦ When the pairs are in cascading configuration, and the ShadowImage for Mainframe
T-VOL and Universal Replicator for Mainframe P-VOL share the volume, the data
consistency cannot be maintained when the data is copied between primary and
secondary storage systems even if you register the journal groups in the extended
consistency group.
◦ When the pairs are in cascading configuration, and the TrueCopy for Mainframe R-VOL
and Universal Replicator for Mainframe P-VOL share the volume, enable the time-stamp
transferring option of all the TrueCopy for Mainframe pairs in the journal group. If the
time-stamp transferring option is not enabled, the data consistency cannot be maintained
when the data is copied between primary and secondary storage systems even if you
register the journal groups in the extended consistency group.
•
Configuring the primary EXCTG:
You need to configure a primary EXCTG, because the primary EXCTG will be necessary if
you need to reverse the primary and secondary sites after a failure occurs. If you reverse the
copy direction when no primary EXCTG is configured, the data update sequence will be
maintained on a journal group basis, but not on an extended consistency group basis.
178 Using Extended Consistency Groups