HP StorageWorks XP24000 Continuous Access Journal Software User and Reference Guide, v01 (T5278-96001, June 2007)

A split (or suspended) Continuous Access Journal secondary data volume has an additional status
called
the consistency status. The consistency status is displayed only at the secondary storage system
and indicates the update sequence consistency of the secondar y data volume with respect to the other
secondary data volumes in the same group. Table 6 on page 37 lists and describes the consistency
statuses for split or suspended Continuous Access Jou rnal secondary data volumes (the consistency status
is
displayed only at the secondary storage system) .
Table 7 Suspend Types (PSUE)
Type
Applies to
Description
PSUE, S-VOL
Failure
Primary data volume,
Secondary data
volume
The primary storage system d etected an error during a secondary
storage system communication or an error d uring an update copy.
In
this case, the seconda ry data volume suspend type is usually
PSUE-S-VOL Failure.
PSUE, MCU
IMPL
Primary data volume,
Secondary data
volume
Theprimary storagesystem could not find valid control information
in its
nonvolatile memory during an IMPL. This condition occurs
only if the primary storage system is without power for more than
48 hours (that is, a power failure and fully discharged backup
batteries).
PSUE, Initial
Copy Failed
Primary data volume,
Secondary data
volume
The Continuous Access Journal pair was suspended before the
initial copy operation was complete. The d ata on the secondary
data volume is not identical to the data on the primary data volume.
PSUE, MCU
P/S O FF
Secondary data
volume
Theprimary storagesystemispowered off.
Suspension Conditions
Continuous Access Journal o perations involve additional suspension conditions related to the
asynchronous journal o perations. Both the primary storage system and secondar y storage system can
detect Continuous Access Journal suspension conditions and suspend Continuous Access Journal pa irs.
The primary storage system stores the differential bitmap for each Continuous Access Journal primary
data volume in the s hared memory. The secondary storage system stores the differential bitmap for each
Continuous Access Journal secondary data volume in the shared memory. When a Continuous Access
Journal pair is suspended, the tracks which contain the following journals are marked in the differential
bitmap as modified (to be copied during the pairresync operation):
• The journal data that was created by the primary storage system, but not yet sent to the secondary
storage system.
After marking these primary data volume tracks as modi fied, the primary storage system discards
this
journal data.
• The journal data that was sent to the secondary storage system, but not acknowledged by the
secondary storage system.
After marking these primary data volume tracks as modi fied, the primary storage system discards
this
journal da ta. This ensures that journal data lost during transmission to the secondary storage
system is identified a n d marked.
• The journal data that reached the secondary storage system, but h as not yet been restored.
After marking these primary data volume tracks as modi fied, the primary storage system discards
this
journal data. Therefore, the secondary storage system can check and mark the journal data
that has not been restored.
The primary storage system does not discard journal data from the master journal volume until
the
primary storage system receives the sequence numbers of the restored journal volumes. The
sequence numbers are included in the read journal commands from the secondar y storage system.
• The p rimary data volume records updated by host-requested write I/Os a fter the pair was
suspended.
Table 8 on page 39 describes the Continuous Access Journal suspension cond itions and indicates which
CU detects the condition and which pairs are suspended. See “General Troubleshooting” on p age 151
for troubleshooting information for Continuous Access Journal suspension conditions.
38
About
Continuous Access Journal Operations