HP StorageWorks XP Remote Web Console Software - Manual (Page 11)

Table 2 XP Continuous Access Storage System Mode (continued)
Description Mode
remote I/O (RIO) from the MCU to the RCU and is not completed within 20 seconds. As the
relevant pair will transit to the suspend status, the differential management for the subsequent
update data to the relevant P-VOL is performed by the P-VOL, and the data is not copied to
the S-VOL. When this mode is ON, if the RIO is not completed within 20 seconds due to a
failure or high load, the effect on the host performance can be reduced. If the relevant pair
belongs to the consistency group in the XP Continuous Access Synchronous mode, all the
pairs in the consistency group transit to the suspend status (PFUS).
Mode 549 OFF: If the RIO is not completed within 20 seconds, the relevant pair will not
transit to the suspend status (PFUS). For the update I/O, depending on the fence level, a
response of Good or Check is reported. The RIO that did not completed in 20 seconds is
retried.
Mode 549 ON: If the RIO is not completed within 20 seconds, the relevant pair will not
transit to the suspend status (PFUS). For the update I/O, depending on the fence level, a
response of Good or Check is reported. The differential management for the subsequent
Write I/O to the P-VOL is performed by the P-VOL, and the data is not copied to the S-VOL.
* PFUS (Suspend status due to overload) is a pair status for RAID Manager only. In the
Remote Web Console, the status is displayed as PSUE (suspend type=Sidefile Overflow).
Mode 697 allows you to check the status of the XP Continuous Access Asynchronous pairs
if XP Continuous Access Asynchronous S-VOLs are shared with XP Business Copy P-VOLs,
and if the split option is going to be performed on XP Business Copy pairs. 697
Mode 697 OFF (default): The XP Continuous Access Asynchronous pair status will not be
checked. The split operation on the XP Business Copy pair is started automatically.
Mode 697 ON: The XP Continuous Access Asynchronous pair status will be checked. The
split operation on the XP Business Copy pair will be started only when all the XP Continuous
Access Asynchronous pairs have agreed on the condition. For more details about the Mode
697 check, see
“XP Business Copy” (page 40) .
Mode 781 allows you to select if the relevant pair will transit to the suspend status (PSUE)
if a P-VOL in XP Continuous Access Synchronous mode receives an update I/O and remote 781
I/O (RIO) from the MCU to the RCU is not completed within 20 seconds. As the relevant
pair is made to transit to the suspend status, the differential management for the subsequent
update data to the relevant P-VOL is performed by the P-VOL, and the data is not copied to
the S-VOL. By setting this mode ON, if the RIO is not completed within 20 seconds due to
a failure or high load, the effect on the host performance can be reduced. If the relevant
pair belongs to the consistency group in XP Continuous Access Synchronous mode, all the
pairs in the consistency group transit to the suspend status (PSUE).
Mode 781 OFF: If the RIO is not completed within 20 seconds, the relevant pair does not
transit to the suspend status (PSUE). For the update I/O, depending on the fence level, a
response of Good or Check is reported. The RIO not completed in 20 seconds is retried.
Mode 781 ON: If the RIO is not completed within 20 seconds, the relevant pair does not
transit to the suspend status (PSUE). For the update I/O, depending on the fence level, a
response of Good or Check is reported. The differential management for the subsequent
Write I/O to the P-VOL is performed by the P-VOL, and the data is not copied to the S-VOL.
*Do not set the modes 549 and 781 at the same time. If both are set at the same time, the mode
549 is prioritized.
Main and Remote Control Units (MCUs and RCUs)
The main control unit (MCU) and remote control unit (RCU) control XP Continuous Access operations:
•
The MCU is the control unit in the primary storage system that controls the P-VOLs of the XP
Continuous Access pairs. The Remote Web Console computer must be LAN-attached to the
MCU of each XP Continuous Access pair. The MCU communicates with the RCU via the
dedicated remote copy connections. The MCU controls the host I/O operations to the XP
Continuous Access P-VOLs as well as the XP Continuous Access initial copy and remote copy
XP Continuous Access Components 11