HP StorageWorks XP Remote Web Console Software - Manual (Page 38)

Suspended TrueCopy for Mainframe Async Pairs
TrueCopy for Mainframe Async operations involve additional suspension conditions related to the
asynchronous recordset operations. Both the MCU and RCU can detect TrueCopy for Mainframe
Asynchronous suspension conditions and suspend TrueCopy for Mainframe Asynchronous pairs.
“TrueCopy for Mainframe Async Suspension Conditions” (page 38) describes the TrueCopy for
Mainframe Asynchronous suspension conditions and indicates which CU detects the condition and
which pairs are suspended. The TrueCopy for Mainframe Asynchronous offloading timer async
option and timeout group options are used to control the TrueCopy for Mainframe Asynchronous
suspension conditions. See
“Resolving TrueCopy for Mainframe Async Suspension Conditions”
(page 182) for troubleshooting information for TrueCopy for Mainframe Asynchronous suspension
conditions.
Table 11 TrueCopy for Mainframe Async Suspension Conditions
TrueCopy for Mainframe Asynchronous
Pairs to be Suspended
Detected by: Suspension Condition
All TrueCopy for Mainframe
Asynchronous pairs with M-VOLs in the
MCU. MCU The MCU could not send a pending
recordset to the RCU before the
offloading timer async option expired.
All TrueCopy for Mainframe
Asynchronous pairs with M-VOLs in the
MCU. MCU During MCU power-on, the MCU
could not establish communication
with the RCU before the RCU Ready
timeout group option expired.
All TrueCopy for Mainframe
Asynchronous R-VOLs in the consistency
group. RCU The RCU could not settle a pending
recordset before the copy pending
timeout group option expired.
All TrueCopy for Mainframe
Asynchronous R-VOLs in the consistency
group. RCU The RCU could not communicate with
the MCU before the copy pending
timeout group option expired.
Only the affected R-VOL. RCU The RCU could not receive the
recordset successfully due to a
hardware failure.
All TrueCopy for Mainframe
Asynchronous R-VOLs in the group, or RCU The RCU detected a logical error while
selecting the recordset to be settled.
only the affected R-VOL, depending on
RCU The RCU could not settle the recordset
due to a hardware failure, a track
condition, or a logical error.
the failure type and error level
TrueCopy for Mainframe Asynchronous
pair option.
The MCU stores a differential data in the shared memory for each TrueCopy for Mainframe
Asynchronous M-VOL, and the RCU stores a differential data in the shared memory for each
TrueCopy for Mainframe Asynchronous R-VOL. When a TrueCopy for Mainframe Asynchronous
pair is suspended, the tracks which contain the following records are marked in the differential
data as modified (to be copied during the resynchronize pair operation):
•
The recordsets that were created by the MCU but not yet sent to the RCU. After marking these
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 M-VOL tracks as modified and discards these recordsets. This ensures that recordsets
which are lost during transmission to the RCU are identified and marked.
•
The recordsets that reached the RCU but have not yet been settled. After marking these tracks
as modified, the RCU discards these recordsets.
•
The M-VOL records updated by host-requested write I/Os after the pair was suspended (same
function as for TrueCopy for Mainframe Synchronous pairs). When a suspended TrueCopy
for Mainframe Asynchronous pair is resynchronized, the contents of the RCU's differential
data are sent to the MCU and merged into the MCU's differential data. The MCU then performs
38 About TrueCopy for Mainframe Operations