Hitachi TrueCopy for z/OS (T1711-96009, June 2006)

34 TrueCopy for the XP1024/XP128/XP12000/XP10000
NOTE: If there is a network problem, lack of bandwidth, or lack of sufficient Fibre links, the sidefile will
grow and the microcode will add delay to host I/O until the sidefile goes below a certain level again.
Disabling this function will cause the pairs to suspend.
SIM reporting for TC390A sidefile conditions is enabled only when SVP mode 118 or 464 is ON (see
Table 4
on page 20). The reported SIMs when SVP mode 118 or 464 is ON, however, do not support a
CLPR. When this SIM is reported to the host, the SIM reference code is indicated as 490x-yy (“x” is CU
number, and “yy” is LDEV number). For more information about the SIM reference code, call your
HP Account Support Representative.
You can disable the command retry delay for a limited number of critical volumes using the special “No
delay” parameter for the CESTPAIR TSO command (see
”CESTPAIR” on page 160). When this parameter is
set, the XP1024/XP128/XP12000/XP10000 will not delay host write I/Os to the M-VOL until the
TC390A sidefile amount reaches the puncture threshold (threshold + 10%). This prevents performance
degradation for critical volumes and should be used only for a small number of volumes.
Figure 5 Graduated delay process for sidefile management
TrueCopy Asynchronous Consistency Group Operations
TC390A consistency groups enable update sequence consistency to be maintained across a group of
volumes. The R-VOLs of the pairs in a consistency group must be located within one RCU (n-to-1
requirement). The TC390A consistency group operations include the following:
• Group options
• Group consistency time
• Group operations
Only TCzA pairs that belong to the same CLPR can be allocated to one consistency group.
Group Options
TC390A provides the following options for each consistency group: Timer Type, Time Out [Copy Pending],
and Time Out [RCU Ready]. These options are selected when you add a group. If you want to change the
timeout options of a group, you must suspend all pairs in the group first. If you want to change the timer
type option, you must delete all pairs. The Timer Type and Time Out [Copy Pending] options must be the