HP XP Continuous Access Software - Manual (Page 38)

The primary array suspends an XP Continuous Access Journal pair when it detects any of the
following suspension conditions:
•
You deleted the data volume pair from the secondary array
•
An error condition related to the secondary array, secondary data volume, or XP Continuous
Access Journal update copy operation
•
The primary array cannot communicate with the secondary array
•
an XP Continuous Access Journal suspension condition
When an XP Continuous Access Journal pair is suspended, the primary array stops performing
journal obtain operations for the pair. The primary array continues accepting write I/Os for the
suspended primary data volume and keeps track of the primary data volume cylinders/tracks
updated while the pair is suspended. Primary and secondary arrays also keep track of any journal
data discarded during the pair suspension. When the suspended XP Continuous Access Journal
pair is resumed (pairresync), the secondary array sends the secondary data volume's bitmap to
the primary array, and the primary array merges the primary and secondary data volumes' bitmaps
to determine which cylinders/tracks are out-of-sync. The primary array merges the primary and
secondary data volumes' bitmaps to identify out-of-sync cylinders/tracks. This method ensures that
all cylinders/tracks containing journal data discarded at the secondary array are resynchronized
at this time.
A split (or suspended) XP Continuous Access Journal secondary data volume has an additional
status called the consistency status. The consistency status is displayed only at the secondary array
and indicates the update sequence consistency of the secondary data volume with respect to the
other secondary data volume in the same group.
Table 5 (page 37) describes consistency statuses
for split or suspended XP Continuous Access Journal secondary data volumes (the consistency status
is displayed only at the secondary array).
Table 6 Suspend types (PSUE)
Description Applies to Type
The primary array detected an error
during secondary array communications
or during update copy. In this case, the
secondary data volume suspend type
is usually PSUE-S-VOL Failure. Primary data volume, Secondary data
volume PSUE, S-VOL Failure
The primary array could not find valid
control information in its nonvolatile
memory during IMPL. This condition
occurs only if the primary array is
without power for more than 48 hours
(for example, a power failure and fully
discharged backup batteries). Primary data volume, Secondary data
volume PSUE, MCU IMPL
The XP Continuous Access Journal pair
was suspended before the initial copy
operation completed. Data on the
secondary data volume is not identical
to data on the primary data volume. Primary data volume, Secondary data
volume PSUE Initial Copy Failed
The primary array is powered off. Secondary data volume PSUE, MCU P/S OFF
XP Continuous Access Journal suspension conditions
XP Continuous Access Journal operations involve additional suspension conditions related to
asynchronous journal operations. The primary and secondary arrays can detect XP Continuous
Access Journal suspension conditions and suspend XP Continuous Access Journal pairs. The primary
array stores a differential bitmap per XP Continuous Access Journal primary data volume in shared
memory. The secondary array stores a differential bitmap per XP Continuous Access Journal
38 Overview of XP Continuous Access Journal