Requirements; Cgroup (Freeze/Run) Command - HP StorageWorks P9000 User Manual

environment. The CGROUP TSO command is used to control I/O operations for Continuous Access
Synchronous Z pairs on a specific MCU RCU pair.
The CGROUP command is supported for P9500 functioning as Continuous Access Synchronous
Z MCUs. The P9500 provides all required host reporting for CGROUP operations (for example,
IEA494I with extended long busy (ELB) state), which is a key component of GDPS operations. For
disaster recovery implementations, you must use P9500s at both sites, since the RCUs will become
MCUs in the event of a disaster.
The CGROUP command has two parameters, FREEZE and RUN. The CGROUP/FREEZE command
stops all host I/O operations to the specified Continuous Access Synchronous Z M-VOLs as well
as all Continuous Access Synchronous Z update copy operations to their associated R-VOLs. The
CGROUP/RUN command changes the pair status to suspended and allows the M-VOLs to start
accepting host I/Os.
CAUTION:
pairs.
The P9500 supports the Business Continuity Manager Freeze/Run commands that are equal to the
CGROUP command. Even if both commands are performed simultaneously, the P9500s find the
appropriate volumes, and can execute the commands. On the other hand, the host cannot detect
which command is performed.
Therefore, do not use the Business Continuity Manager Freeze/Run commands and the CGROUP
command at the same time. For further information and instructions on Business Continuity Manager,
see the HP StorageWorks P9000 for Business Continuity Manager Software User Guide.

Requirements

The CGROUP command can only be issued to a Continuous Access Synchronous Z M-VOL or a
simplex volume in the MCU. If CGROUP is issued to a Continuous Access Synchronous Z R-VOL,
the RCU will reject the CGROUP command (F/M=0F, Continuous Access Synchronous Z error
code=58).
The requirements for CGROUP (FREEZE/RUN) support are:
MCU: The MCUs to which the CGROUP command will be issued must be P9500 storage
systems (all mainframe and multiplatform storage systems are both supported). For disaster
recovery implementations, you must use P9500 storage systems at both sites, since the RCUs
will become MCUs in the event of a disaster.
PPRC: The host systems at the main and remote sites must have IBM PPRC support as well as
the PPRC ERP PTF.
SSIDs: The MCUs to which the CGROUP command will be issued must have consecutive SSIDs.
The HP representative configures the SSIDs on the P9500 SVP.
CAUTION:
Reconfiguring SSIDs is therefore a disruptive event that must be carefully planned.

CGROUP (FREEZE/RUN) command

The CGROUP TSO command specifies:
The device (LDEV ID of Continuous Access Synchronous Z M-VOL or simplex volume) (DEVN
parameter).
The MCU (S/N and lowest SSID in CU) (PRIM parameter).
The RCU (S/N and lowest SSID in CU) (SEC parameter).
The CGROUP TSO command has the following two options:
90 Using PPRC commands for Continuous Access Synchronous Z
The P9500 executes the CGROUP command on Continuous Access Synchronous Z
MVS requires that the storage system be offline during SSID changes.