HP XP Continuous Access Software - Manual (Page 45)

shared memory. When a Continuous Access XP Journal pair is suspended, tracks containing the following
journal are marked in the differential bitmap as modified (to be copied during the pairresync operation):
• Journal data the primary array has created, but has not sent to the secondary array yet
After marking these primary data volume tracks as modified, the primary array discards the journal
data.
• Journal data that has been sent to the secondary array, but has not been acknowledged by
the secondary array
After marking these primary data volume tracks as modified, the primary array discards the journal
data. This ensures that journal data lost during transmission to the secondary array is identified
and marked.
• Journal data that has reached the secondary array, but has not been restored yet
After marking these primary data volume tracks as modified, the primary array discards the journal
data. Therefore, the secondary array can check and mark journal data that has not been restored.
The primary array does not discard journal data from the master journal volume until the primary
array receives the restored journal volumes' sequence numbers, which are included in read journal
commands from the secondary array.
• Primary data volume records updated by host-requested write I/Os after the pair was suspended
Table 8 describes Continuous Access XP Journal suspension conditions and indicates which CU
detects the condition and which pairs are suspended. See Displaying the History Operation pane for
troubleshooting information for Continuous Access XP Journal suspension conditions.
Table 8 Continuous Access XP Journal suspension conditions
Suspension condition Detected by Continuous Access XP Journal pairs to
be suspended
The secondary array could not copy the
journal data successfully due to a hardware
failure or logic error.
RCU All Continuous Access XP Journal secondary
data volumes in the journal groups, or the
affected secondary data volume
The secondary array detected a logical
error while selecting the journal data to be
restored.
RCU All Continuous Access XP Journal secondary
data volumes in the journal group, or only
the affected secondary volume
The secondary array could not restore the
journal data due to a hardware failure,
track condition, or logical error.
RCU All Continuous Access XP Journal secondary
data volumes in the journal groups, or the
affected secondary data volume
Continuous Access XP Journal user guide 45