HP StorageWorks Continuous Access XP user guide for the XP10000/XP12000 (December 2005)

18 Continuous Access XP for the XP10000/XP12000
• CU Free if you set the MCU-RCU path and specify CU Free.
For more information, see ”Preparing for disaster recovery” on page 105.
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 XP10000/XP12000 as initiator ports. Use
the Port Change operation (see ”Port change operation” on page 74) to change the configuration of the
XP10000/XP12000 Fibre Channel ports (ordinary target port, initiator port, or RCU target port) as
needed.
NOTE: Initiator ports cannot communicate with hosts, but are used exclusively as Continuous Access XP
talkers. Ordinary target ports can be used only for host connect (not for Continuous Access XP).
RCU target ports are (Continuous Access XP) dedicated Fibre Channel interface ports on the remote disk
array (RCU) to which MCUs (initiator ports) are connected. You can configure Fibre Channel interface
ports of the XP10000/XP12000 as RCU target ports. For performance reasons, RCU target ports should
not be shared with host connects.
Remote control ports (RCPs) and local control ports (LCPs)
Remote control ports (RCPs) are dedicated serial interface ports on the MCU to which RCUs are connected.
RCPs emulate host processor channels, enabling MCUs to send write I/O operations directly to RCUs.
RCPs support the dynamic switching capability provided by ESCDs. You can configure serial interface ports
of the disk array as RCPs. Use Continuous Access XP to change the configuration of disk array serial ports
(LCP or RCP) as needed (see ”Port change operation” on page 74).
Local control ports (LCPs) are used for host processor channel interfaces. All serial interface ports on the
disk array have a default setting of LCP. An RCU port connected to an MCU must be in LCP mode to
receive remote copy I/O operations from the MCU.
Two or more RCPs must be configured before you can add RCUs and create Continuous Access XP volume
pairs. RCPs cannot communicate with host processor channels and are dedicated to Continuous Access XP
operations. Host channel interface paths must be connected to other interface ports on the disk array.
Serial interface ports, 1S-1Z and 2S-2Z, cannot be specified as RCPs.
CHA package ports added to DKA slots cannot be specified as RCPs.
Command View XP management station or XP Remote Web Console
The Command View XP management station is attached to the XP10000/XP12000 on the internal LAN
via a TCP/IP connection. The Command View XP management station communicates with each attached
XP10000/XP12000.
The Command View XP management station at the primary site must be connected to the MCU of each
Continuous Access XP pair. A second Command View XP management station should be installed at the
remote site and connected to the RCUs. With another Command View XP management station at the
remote site, you can modify the Continuous Access XP Asynchronous options of the RCU (for example,
pending update data rate or offloading timer) and access the Continuous Access XP S-VOLs (for example,
to perform media maintenance). To perform Continuous Access XP operations in the reverse direction from
the remote site to the primary site (for example, disaster recovery), Continuous Access XP simplifies and
expedites this process.
Alternatively, you can access XP Remote Web Console directly on the MCUs and RCUs to manage their
respective disk arrays.
Host failover software
Host failover software, which transfers information between host servers at primary and remote sites, is a
critical component of any disaster recovery effort. Host failover is configured using the host failover
software product for the platform (such as Microsoft
®
Cluster Server or HP Cluster Extension XP),