HP XP P9500 Storage - Manual (Page 27)

Figure notes:
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RAID Manager manages the consistency group on all primary and secondary system. Business
Continuity Manager cannot be used with multiple systems.
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Open and mainframe volumes (P-VOLs/M-VOLs) receive I/O requests from their applications
at the primary (main) site, and data in the volumes is updated.
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Continuous Access Synchronous or Continuous Access Synchronous Z runs the copy operation
in the consistency group.
•
When the open or mainframe host system guarantees the update order, then data consistency
in P-VOLs and S-VOLs is insured. When the host system does not guarantee update order,
data consistency is not insured.
Consistency group requirements
Requirements are provided for the following consistency group configurations.
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Consistency group between one primary and secondary system (page 27)
•
Consistency group between multiple primary and secondary systems (page 27)
Consistency group between one primary and secondary system
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A consistency group is configured on the primary and secondary system.
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When you have multiple pairs in the same consistency group, they must exist between the
same primary and secondary systems.
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A pair can be assigned to only one consistency group.
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Continuous Access Synchronous pairs can be in the same consistency group as Continuous
Access Synchronous Z pairs. Use the same consistency group number for both types.
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A consistency group can have 8,192 pairs, maximum. (Consistency group 127 can have
4,096 pairs, maximum.)
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One primary and one secondary system can have 128 consistency groups, maximum.
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The number for a new consistency group must be an unused number.
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If you use BCM to resynchronize a Cnt Ac-S Z pair in an open/mainframe consistency group
with one primary and secondary system, all pairs in the consistency group are resynchronized.
Even if a Cnt Ac-S S-VOL is being accessed by a host, the pair is nevertheless resynchronized
with the others. Make sure to check the status of all pairs in the consistency group before
resynchronizing.
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If you use BCM to delete a Cnt Ac-S Z pair in an open/mainframe consistency group with
one primary and secondary system, only the Cnt Ac-S Z pairs are deleted. Use RAID Manager
to delete the Cnt Ac-S pairs.
Consistency group between multiple primary and secondary systems
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All requirements for a consistency group between one primary and one secondary system
apply to a consistency group between multiple primary and secondary system.
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Both primary and secondary system must be XP P9500s. No other model can be used.
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A maximum of four primary and four secondary (paired) systems may be assigned to a
consistency group.
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The microcode for both primary and secondary systems must support consistency groups
between multiple primary and secondary systems; otherwise, pair creation results in failure.
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You must install the version of RAID Manager that supports a consistency group consisting of
multiple MCUs and RCUs.
Consistency group planning 27