Pair options, Changing pair options – HP StorageWorks XP Remote Web Console Software User Manual
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4
LUN 04
5
LUN 01, 02
The MCU immediately starts the initial copy operations for LUNs 003, 005, 000, and 004,
immediately; starts LUN 001 when one of the first four initial copy operations is complete, and
then starts LUN 002 when the next initial copy operation is complete. If more XP Continuous Access
pairs are created, the MCU also prioritizes the initial copy operations by the time requested so
that all pairs in the first group are started before any pair in the next group is started.
If the time-out error occurs during the Paircreate operation, the copy operation may not be executed
correctly in the order that you have set with the Priority parameter. The time-out error may be
caused by the CU configuration or a remote copy path error. Review the error, release the pair
with the error, and then retry the Paircreate operation.
Pair Options
When you create new XP Continuous Access pairs, you select the pair options on the Paircreate
dialog box. You can change the fence level and error level pair options after a pair has been
added. You cannot change the difference management or CT group of an existing pair. You need
to release and then restart the pair to change these options.
P-VOL Fence Level (Synchronous only): Specifies the conditions under which the MCU will reject
write operations to the P-VOL, which is known as fencing: never, data, or status (default = Never).
This parameter is very important for disaster recovery planning (see
).
•
Never: The P-VOL will never be fenced. If the XP Continuous Access pair is split or suspended,
write operations to the P-VOL will be accepted. (The fence level for all XP Continuous Access
Asynchronous pairs is Never.)
•
Data: The P-VOL will be fenced when the MCU cannot successfully execute an update copy
operation for any reason.
•
Status: The P-VOL will be fenced only if the MCU is not able to change the S-VOL status to
suspended when an update copy operation fails. If the MCU changes the S-VOL status to
suspended, subsequent write operations to the P-VOL will be accepted, and the MCU will
keep track of all P-VOL updates while the pair is suspended.
CT Group (Asynchronous only): Specifies the consistency group number for new pairs. All XP
Continuous Access Asynchronous pairs must be assigned to a consistency group. To change the
consistency group to which a pair is assigned, you must release and then restart the pair with the
desired group selected.
Error level (Asynchronous only) (default = Group):
•
Group: When the specified pair is suspended, all pairs in the same group will be suspended,
even if the failure affects only that pair and not the entire group.
IMPORTANT:
Select the Group error level for all pairs that are essential to disaster recovery.
Suspended XP Continuous Access Asynchronous S-VOLs with the LU error level should not be
used for disaster recovery.
•
LU: If the failure affects only the specified pair, then only that pair will be suspended. A failure
that affects an entire group will always result in the suspension of all pairs in the group, as
well as all other affected XP Continuous Access pairs.
Changing Pair Options
The Change Pair Option dialog box (see
“Change Pair Option Dialog Box (Synchronous and
) allows you to change the pair options (fence level, error level) for
existing XP Continuous Access pairs. To open the Change Pair Option dialog box, click the Pair
Changing Pair Options
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