Rcu Option Pane - HP xp12000 User Manual

• Cancel button: Cancels settings made on the Add RCU pane, and closes the pane.
Figure 29

RCU Option pane

Use the RCU Option pane to set the options for the RCU.
• Minimum Paths: Minimum number of paths required for each RCU connected to the current MCU. The
default is one. If you specify a number that is larger than the number of paths set on the Register RCU
pane or the number of paths falls below this number (for example, failed path), an error occurs. When
errors occur, the MCU suspends all affected Continuous Access XP (and any mainframe) pairs to
prevent remote copy operations from adversely affecting performance due to the inadequate number of
paths. If the MCU contains Continuous Access XP pairs, which contain critical data for disaster
recovery, set minimum number of paths to one, so Continuous Access XP operations continue even if
there is only one path to an RCU. If you need high performance at the MCU, set minimum number of
paths to two or more (up to eight per CU image), depending on number of pairs managed by the
MCU.
CAUTION:
dropped below this setting, the P-VOL fence-level pair option (see
volume pairs
P-VOLs are fenced (that is, all write operations are rejected).
• RIO MIH Time: Time value for the remote I/O (RIO) missing interrupt handler (MIH), which is the wait
time until data transfer from the MCU to RCU is complete. The RIO MIH time must be from 10 to 100
seconds. The default is 15 seconds. This setting is available for both serial and Fibre Channel
interfaces.
• Round Trip Time (ms): Used for initial copy operations. This setting give a priority to a remote I/O for
an update copy operation.
• Cancel button: Cancels the registering RCU operation.
• Set button: Sets the registering RCU operation with the option set on the RCU Option pane.
The Round Trip Time setting is used for initial copy operations. This setting gives priority to remote I/Os for
update copy operations.
When an initial copy operation is in progress, the copy pace is automatically adjusted based on the actual
time required for initial copy, which can be obtained by subtracting the specified Round Trip Time
(obtained using the formula below) from the remote I/O response time. If the actual time required for the
initial copy operation is large, the update copy workload is relatively high. Therefore, the copy pace of the
initial copy is slowed. When the time is relatively small, the copy pace speeds up to the specified value. In
this way, the influence of the exclusive line use in the initial copy operation on the host performance is
curbed.
NOTE: This option is available only for Continuous Access XP Sync pairs. For Continuous Access XP Aync
pairs, this option value is invalid.
68 Continuous Access XP for the XP12000/XP10000
If Continuous Access XP volume pairs are suspended because number of paths
(Paircreate)" on page 93) determines whether Continuous Access XP Synchronous
"Creating Continuous Access XP