Hitachi TrueCopy for IBM z/OS User and Reference Guide (T5211-96001, June 2007)

About TrueCopy for z/OS Operations 2-7
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
Control Units (MCUs and RCUs)
The main control unit (MCU) and remote control unit (RCU) control TCz
operations:
 The MCU is the control unit (CU) in the main storage system which controls
the M-VOLs of the TCz pairs. The Storage Navigator computer must be LAN-
attached to the MCU of each TCz pair. The MCU communicates with the RCU
via the dedicated remote copy connections. The MCU controls the host I/O
operations to the TCz M-VOLs as well as the TCz initial copy and remote copy
operations between the M-VOLs and R-VOLs. The MCU also manages the TCz
pair status and configuration information.
• The RCU is the CU in the remote storage system which controls the R-VOLs of
the TCz pairs. The RCU assists in managing the TCz pair status and
configuration (e.g., rejects write I/Os to TCz R-VOLs). The RCU executes the
remote copy operations issued by the MCU. The secondary Storage Navigator
computer should be attached to the RCUs at the remote site on a separate
LAN. The RCUs should also be attached to a host system to allow sense
information to be reported in case of a problem with a secondary volume or
remote storage system and to provide disaster recovery capabilities.
The MCU and RCU can be defined separately for each TCz pair. The USP V CU
can function simultaneously as an MCU for one or more M-VOLs and as an RCU
for one or more R-VOLs, provided the remote copy connections and ports are
properly configured. The USP V provides two logical disk controllers (LDKC).
Each LDKC provides up to 255 logical CUs (00-FE), with each CU controlling up
to 256 logical devices (LDEVs).
TCz operations can be performed on all logical devices (LDEVs) without the
command device for Business Continuity Manager in all logical CUs. The TCz
software allows you to select the desired CU in the connected MCU and specify
the desired CU in the RCU. For detailed information about the command device
for Business Continuity Manager, please refer to the user documentation for
Business Continuity Manager.
Note: This document provides instructions for performing TCz operations with
the USP V as the MCUs. If you are using non-USP V models as MCUs, please
refer to the TrueCopy for z/OS User and Reference Guide for the storage
system. Other Hitachi RAID storage systems can be used as RCUs connected
to the USP V MCU for TCz Synchronous and/or Asynchronous operations.
Caution: If you are creating a TCz pair with different series of storage
systems (e.g., USP V and TagmaStore USP), make sure that each storage
system has a unique serial number. It is possible that a serial number overlap
could occur (although this would be extremely rare). If you have two storage
systems with the same serial number and you need to configure remote copy
pairs between the two storage systems, please contact your Hitachi account
team for assistance.