HP StorageWorks XP Remote Web Console Software - Manual (Page 35)

Continuous Access Asynchronous pair is resynchronized, the RCU sends the S-VOL differential
data to the MCU, and the MCU merges the P-VOL and S-VOL differential data to determine which
tracks are out-of-sync. This method ensures that all tracks that contain recordsets that were discarded
at the RCU are resynchronized at this time.
A suspended (or split) XP Continuous Access Asynchronous S-VOL has an additional status called
the consistency status. The consistency status is displayed only at the RCU and indicates the S-VOL’s
update sequence consistency with respect to the other S-VOLs in the same group. See
“Consistency
Status for Split or Suspended XP Continuous Access Asynchronous S-VOLs” (page 34) for a
description of consistency statuses for suspended/split XP Continuous Access Asynchronous S-VOLs.
Table 12 Suspend Types (PSUE)
Description Applies to Type
The MCU detected an error condition at the RCU that caused
the MCU to suspend the XP Continuous Access pair. The S-VOL
suspend type is S-VOL Failure. P-VOL, S-VOL by RCU
The MCU detected an error during RCU communications or
an IO error during update copy. In this case, the S-VOL P-VOL, S-VOL S-VOL Failure
suspend type is usually S-VOL Failure. This suspend type is
also used when the number of paths falls below the minimum
number of paths setting on the RCU Option dialog box.
The MCU could not find valid control information in its
nonvolatile memory during IMPL. This condition occurs only if P-VOL, S-VOL XP
Continuous Access
Async MCU IMPL
the MCU is without power for more than 48 hours (that is,
power failure and fully discharged backup batteries).
The MCU suspended the pair before the initial copy operation
was complete. The data on the S-VOL is not identical to the
data on the P-VOL. P-VOL, S-VOL Initial Copy Failed
The RCU received a request from the MCU to suspend the
S-VOL due to an MCU power-off. The RCU suspended all S-VOL
(XP Continuous
Access
Asynchronous only)
MCU P/S OFF
S-VOLs of the corresponding pairs. The P-VOL status does not
change due to an MCU power-off.
P-VOL, S-VOL Sidefile overflow 1. The amount of the sidefile exceeds the specified current
pending update data rate, and the RCU data is not
transferred within the specified offloading timer.
(XP Continuous
Access
Asynchronous only)
2. In case the system option mode 549 is ON, the suspend
occurred due to the RIO completion waiting TOV. The
suspend type is Sidefile Overflow.
XP Continuous Access Asynchronous Suspension Conditions
XP Continuous Access Asynchronous operations involve additional suspension conditions related
to recordset operations. Both the MCU and RCU can detect XP Continuous Access Asynchronous
suspension conditions and suspend XP Continuous Access Asynchronous pairs. The MCU stores
the differential data per XP Continuous Access Asynchronous P-VOL to the shared memory. The
RCU stores the differential data per XP Continuous Access Asynchronous S-VOL to the shared
memory. When an XP Continuous Access Asynchronous pair is suspended, the tracks that contain
the following records are marked in the differential data as modified (to be copied during the
pairresync operation):
•
The recordsets that were created by the MCU, but not yet sent to the RCU. After marking these
P-VOL tracks as modified, the MCU discards these recordsets.
•
The recordsets that were sent to the RCU, but not acknowledged by the RCU. The MCU marks
these P-VOL tracks as modified and discards these recordsets. This ensures that recordsets lost
during transmission to the RCU are identified and marked.
Pair Status 35