HP XP P9000 Continuous Access Synchronous for Mainframe Systems User Guide

However, if Cnt Ac-S Z pairs are registered in consistency groups, they are not placed
in SCP status, even if the CGROUP (FREEZE) command is received.
◦ Stops update copy operations to associated S-VOLs
Logical paths are blocked between the specified MCU and RCU to stop Cnt Ac-S Z update
copy operations to the S-VOLs.
◦ Suspends Cnt Ac-S Z pairs with P-VOLs on the specified MCU CU. However, if Cnt Ac-S
Z pairs are registered in consistency groups, they are not suspended, even if the CGROUP
(FREEZE) command is received.
• CGROUP RUN:
◦ Starts host I/O to P-VOLs again
- Presents a state change interrupt (SCI) to the hosts, so that they reissue the I/Os that
were waiting while the P-VOLs were in the SCP state.
- Changes the P-VOL fence level to Never (PPRC CRIT=NO), so that the suspended P-VOLs
accept host write I/O operations.
The CGROUP FREEZE/RUN command is supported for XP P9500 when it functions as the MCU.
The XP P9500 provides all required host reporting for CGROUP operations (for example, IEA494I
with extended long busy (ELB) state), which is a key component of operations in IBM’s
Geographically Dispersed Parallel Sysplex (GDPS) environment, which also uses this command.
For disaster recovery implementations, XP P9500s must be used at both sites, because the RCUs
will be switched to MCUs.
CAUTION: XP P9500 also supports the Business Continuity Manager Freeze and Run commands,
which are equivalent to the TSO CGROUP command. If both commands are performed
simultaneously, the XP P9500s find the appropriate volumes and run the commands.
However, in this situation, the host cannot detect which command is performed. Therefore, it is
important not to use the Business Continuity Manager Freeze/Run commands and the CGROUP
command at the same time.
CGROUP and FREEZE/RUN requirements
The CGROUP command can only be issued to an P-VOL or a simplex volume in the MCU. If issued
to an S-VOL, the RCU rejects it with F/M=0F, reason code=58.
The requirements for CGROUP FREEZE/RUN support are:
• MCU: The MCUs to which the CGROUP command will be issued must be XP P9500 storage
systems (all mainframe and multi-platform systems are supported). For disaster recovery
implementations, you must use XP P9500 storage systems at both sites, because the RCUs will
become MCUs in the event of a disaster.
• PPRC: The host systems at the primary and secondary sites must have IBM PPRC support and
the PPRC ERP PTF
116 Pair operations using PPRC