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

A-32 Using PPRC Commands for TrueCopy for z/OS
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
CGROUP (FREEZE/RUN) Command
The CGROUP TSO command specifies:
• the device (LDEV ID of TCz 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:
• FREEZE (3990 only): When CGROUP is issued with the FREEZE option , the
MCU:
– Blocks the logical path(s) between the specified MCU CU and RCU CU to
stop all TCz update copy operations to the R-VOLs in the specified RCU.
– Presents state change pending (SCP) with extended long busy status to
host I/O requests, which causes the host to queue I/Os for the M-VOLs.
SCP is indicated until the CGROUP/RUN command is issued or until the
SCP time expires.
Note: After all logical MCU-RCU paths are established, make sure to
specify the desired SCP time (0-600 seconds) for the MCU using the CU
Option dialog box.
Note: If the specified MCU does not have any TCz M-VOLs, the FREEZE
command is executed without performing any operations (paths are not
blocked, SCP is not indicated).
Note: For 2105 and 2107 emulation, use the CESTPATH CGROUP option to
control freeze.
• RUN: When CGROUP is issued with the RUN option, the MCU:
– Suspends all TCz pairs with M-VOLs on the specified MCU CU.
– Presents a state-change-interrupt (SCI) to the host(s), so that the host(s)
re-issue the I/Os which were waiting while the M-VOLs were in the SCP
state.
– Changes the TCz M-VOL fence level to Never (PPRC CRIT=NO), so that
the suspended M-VOLs accept host write I/O operations.