HP XP Continuous Access Software - Manual (Page 44)

Continuous Access XP Journal suspend types
Table 7 describes the Continuous Access XP Journal suspend types, which indicate the reason for the
suspension. Continuous Access XP Journal pairs can be suspended by the primary or secondary array.
For more information, see Continuous Access XP Journal suspension conditions .
The primary array suspends a Continuous Access XP 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 Continuous Access
XP Journal update copy operation
• The primary array cannot communicate with the secondary array
• A Continuous Access XP Journal suspension condition
When a Continuous Access XP 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 Continuous Access XP 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) Continuous Access XP 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 6 describes consistency statuses for split or suspended
Continuous Access XP Journal secondary data volumes (the consistency status is displayed only at
the secondary array).
Table 7 Suspend types (PSUE)
Type Applies to Description
PSUE, S-VOL Failure Primary data volume,
Secondary data volume
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.
PSUE, MCU IMPL Primary data volume,
Secondary data volume
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).
PSUE Initial Copy Failed Primary data volume,
Secondary data volume
The Continuous Access XP 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.
PSUE, MCU P/S OFF Secondary data volume The primary array is powered off.
Continuous Access XP Journal suspension conditions
Continuous Access XP Journal operations involve additional suspension conditions related to asynchronous
journal operations. The primary and secondary arrays can detect Continuous Access XP Journal
suspension conditions and suspend Continuous Access XP Journal pairs. The primary array stores a
differential bitmap per Continuous Access XP Journal primary data volume in shared memory. The
secondary array stores a differential bitmap per Continuous Access XP Journal secondary data volume in
44 Overview of Continuous Access XP Journal