HP StorageWorks XP Remote Web Console Software - Manual (Page 34)

34 Continuous Access XP Journal
Continuous Access XP Journal secondary data volumes (the consistency status is displayed only at the
secondary disk array).
Continuous Access XP Journal suspension condition
Continuous Access XP Journal operations involve additional suspension conditions related to asynchronous
journal operations. The primary and secondary disk arrays can detect Continuous Access XP Journal
suspension conditions and suspend Continuous Access XP Journal pairs. The primary disk array stores the
differential bitmap per Continuous Access XP Journal primary data volume in shared memory. The
secondary disk array stores the differential bitmap per Continuous Access XP Journal secondary data
volume in shared memory. When a Continuous Access XP Journal pair is suspended, the tracks containing
the following journal are marked in the differential bitmap as modified (to be copied during the pairresync
operation):
• Journal data the primary disk array has created, but has not sent to the secondary disk array yet
After marking these primary data volume tracks as modified, the primary disk array discards the
journal data.
• Journal data that has been sent to the secondary disk array, but the secondary disk array has not
acknowledged
After marking these primary data volume tracks as modified, the primary disk array discards the
journal data. This ensures that journal data lost during transmission to the secondary disk array is
identified and marked.
• Journal data that has reached the secondary disk array, but has not been restored yet
After marking these primary data volume tracks as modified, the primary disk array discards the
journal data. Therefore, the secondary disk array can check and mark journal data that has not been
restored.
The primary disk array does not discard journal data from the master journal volume until the primary
disk array receives the restored journal volumes’ sequence numbers, which are included in read journal
commands from the secondary disk array.
• Primary data volume records updated by host-requested write I/Os after the pair was suspended
Table 7 Suspend types (PSUE)
Type Applies to Description
PSUE, S-VOL Failure Primary data volume,
Secondary data volume
The primary disk array detected an error during
secondary disk 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 disk array could not find valid control
information in its nonvolatile memory during IMPL.
This condition occurs only if the primary disk 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 was
complete. 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 disk array is powered off.