Continuous Access Xp Initial Copy And Pair Options Of The Paircreate Pane - HP StorageWorks XP12000 User Manual

• Priority: Priority (scheduling order) of initial copy operations.
• Diff: In the measurement of the Cylinder or the Track, Continuous Access XP manages differentials
among data.
• CTG: Consistency group used for pair created (Asynchronous pairs only).
• ErrLvl: Error level, Group or LU. When a failure occurs, pairs in the same group or in an LU are
suspended (Asynchronous pairs only).

Continuous Access XP initial copy and pair options of the Paircreate pane

Continuous Access XP initial copy and pair options specify the fence level, initial copy parameters, and
asynchronous parameters. Initial copy and pair options are selected on the Paircreate pane. While the
initial copy operation is in progress, the initial copy options cannot be changed unless you delete
(pairsplit-S) and then restart (paircreate) the pair. After the initial copy operation is complete, you can
only change Continuous Access XP pair options (Fence Level and Error Level).
Fence Level (Continuous Access XP Synchronous only)
Fence Level: Conditions under which the MCU rejects write operations to the P-VOL, which is known as
"fencing." This option is very important for disaster recovery planning.
• Never: The P-VOL is never fenced. If the Continuous Access XP volume pair is split or suspended,
write operations to the P-VOL are accepted.
• Data: The P-VOL is fenced when the MCU cannot successfully execute an update copy operation
for any reason.
• Status: The P-VOL is fenced only if the MCU cannot 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 are accepted, and the MCU tracks all P-VOL updates while the
pair is suspended.
Initial Copy parameters
Initial Copy: Initial copy mode for new pairs. The default is Entire Volume.
• Entire Volume: The initial copy operation copies all cylinders on the P-VOL (except diagnostic
and unassigned alternate tracks) to the S-VOL.
• No Copy: The initial copy operation is not performed. The MCU performs update copy operations
as needed.
CAUTION:
Ensure that the P-VOL and S-VOL are already identical when using this setting.
Initial Copy Pace: Maximum number of tracks (1-15) that can be copied at one time by the Continuous
Access XP initial copy operation before the MCU accepts another host request for that P-VOL. A high
setting (for example, 15 tracks) speeds up the initial copy operation, but may affect the disk array's I/O
performance if the P-VOL experiences high write I/O activity. A lower setting (for example, 3 tracks)
slows down the initial copy operation to minimize impact on the disk array's I/O performance.
Priority: Order in which initial copy operations are performed if the number of requested initial copy
operations is greater than the maximum initial copy activity setting on the RCU Option pane (see
Registering RCUs (Add
Use the Continuous Access XP initial copy priority option to spread initial copy operations across disk
array groups and disk array domains (ACP pairs) to reduce initial copy time and host I/O contention.
For example, suppose the maximum initial copy activity setting is four, and you add six Continuous
Access XP pairs at one time (for LUNs 00 through 05) with the initial copy priority set as follows:
106
Continuous Access XP for the Array
RCU)). The highest priority is 1, and the lowest priority is 256 (current default = 32).