HP XP7 Storage User Manual
Page 161
NOTE:
•
pairsplit ("simplex -S") of Snapshot volume is returned without verification of state transition
that waits until SMPL state. In SMPL state, the volume that was S-VOL becomes R/W disable
and data is discarded.
•
In the "PSUE" state, Snapshot does not manage for differential data between the primary
volume and secondary volume.
Continuous Access Asynchronous, Continuous Access Synchronous, and Continuous
Access Journal volumes
Continuous Access Asynchronous/Continuous Access Journal provides paired volumes that use
asynchronous transfer to ensure the sequence of writing data between the primary volume and
secondary volume. The sequence of writing data between the primary and secondary volumes is
guaranteed within each consistency (CT) group (see
).
Figure 52 Continuous Access Asynchronous consistency groups
Restrictions
•
Group definition of Continuous Access Asynchronous/Continuous Access Journal/Continuous
Access Synchronous volume: All volumes in a group must be contained within the same storage
system. If two or more groups of RAID Manager include the same CT group (CTGID), then
pair operation of the group specification is handled in CT group entirety.
•
Registration of CTGID number and limitations: RAID Manager registers CTGID to RAID disk
array automatically when paired volumes are created by paircreate command, and groups
of configuration definition files are mapped to CTGID. The maximum number of CT groups is
256 for P9500 and XP24000/XP20000 Disk Array (CTGID0 to CTGID255), 128 for XP12000
Disk Array/XP10000 Disk Array (CTGID0 to CTGID127), 64 for XP1024/XP128 Disk Array
(CTGID0-CTGID63), and 16 for XP512/XP48 Disk Array (CTGID0 to CTGID15). Continuous
Access Asynchronous/Continuous Access Journal pair command is terminated with
EX_ENOCTG when the maximum number of CT groups is exceeded.
•
Relationships between CTGID and Journal ID: CT group numbers 0-127 are used for Continuous
Access Asynchronous, Continuous Access Synchronous, and Continuous Access Journal. The
rest of the CT group numbers 128-255 are used only for Continuous Access Journal, and are
mapped to the journal.
Continuous Access Synchronous, Business Copy, and Continuous Access Journal operations
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