Remote Copy Connections; Initiator Ports And Rcu Target Ports - HP xp12000 User Manual

Only Continuous Access XP Asynchronous pairs belonging to the same CLPR can be allocated to one
Continuous Access XP consistency group. For more information about CLPRs, see the HP StorageWorks XP
Disk/Cache Partition user guide.

Remote copy connections

Remote copy connections are physical paths MCUs use to communicate with RCUs. The number of
physical paths in the MCU is limited to eight per logical CU image. MCUs and RCUs are connected via
Fibre Channel interface cables.
When Fibre Channel interface connections are used, switches are required for distances greater than 0.5
km (1,640 feet). Distances up to 1.5 km (4,920 feet, 0.93 miles) are supported with dual switches utilizing
shortwave connections. Distances up to 10 km (6.2 miles) are supported using dual switches with
longwave connections. Distances up to 30 km (18.6 miles) are supported using dual switches with
longhaul connections. Distances up to 100 km are supported by using dual switches with DWDM. See
"Fibre Channel remote copy
configuring Fibre Channel remote copy connections.
The MCU-to-RCU remote copy configuration for Continuous Access XP Asynchronous has different
requirements than the Continuous Access XP Synchronous configuration, as follows:
• Continuous Access XP Synchronous supports 1-to-n and n-to-1 remote copy connections (n≤ 4). One
MCU can be connected to as many as four RCUs. One RCU can be connected to as many as four
MCUs (one MCU/RCU = one physical CU, including all sixteen CU images).
• Continuous Access XP Asynchronous supports 1-to-1 remote copy connections within the same
consistency group. P-VOLs and S-VOLs of pairs in a consistency group must be within one physical
MCU and one physical RCU. This configuration ensures backup integrity for a data set spread across
multiple volumes within one XP12000/XP10000 (such as large databases).
Continuous Access XP Asynchronous 1-to-n and n-to-1 (n ≤4) configurations (one main disk array and
multiple remote disk arrays) are valid for Continuous Access XP Asynchronous if all volumes belonging
to a single consistency group are only 1-to-1.
• With direct connect Fibre Channel (no switch), fibre remote copy supports 1-to-1 remote copy
connections. One XP12000/XP10000 as an MCU can be connected to only one XP12000/XP10000
as an RCU via optical fibre cables. For CU images within one XP12000/XP10000, 1-to-4 and 4-to-1
remote copy connections are supported via direct connects or an FC switch.
HP strongly recommends you establish at least two independent remote copy connections (one per cluster)
between each MCU and RCU to provide hardware redundancy for this critical communications path.
NOTE: To recover data from a disaster, prepare the RCU-MCU paths in addition to the usual MCU-RCU
paths. For more information, see
When you set the RCU-MCU path, you must also specify:
• The same combination of CU images as when you set the MCU-RCU path if you set the MCU-RCU path
and specify the CU image.
• CU Free if you set the MCU-RCU path and specify CU Free.
For more information, see

Initiator ports and RCU target ports

Initiator ports are dedicated Fibre Channel interface ports on the main disk array (MCU) to which RCUs
(RCU target ports) are connected. Initiator ports connect to RCUs to send write I/O operations directly to
RCUs. You can configure Fibre Channel interface ports of the XP12000/XP10000 as initiator ports. Use
the Port Change operation (see
XP12000/XP10000 Fibre Channel ports (ordinary target port, initiator port, or RCU target port) as
needed.
connections" on page 34 for further information about installing and
"Registering RCUs (Add
"Preparing for disaster recovery" on page 108.
"Port change operation" on page 76) to change the configuration of the
Continuous Access XP user guide for the XP12000/XP10000
RCU)" on page 66.
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