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

6-24 Performing TrueCopy for z/OS Pair Operations
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
Resynchronizing TrueCopy for z/OS Pairs
While a TCz pair is suspended, the MCU does not perform any update copy
operations.
• For a suspended TCz Synchronous pair, the MCU may or may not continue
accepting write I/Os for the M-VOL depending on the M-VOL fence level and
suspend kind option (if user-requested). If the MCU accepts write I/Os for a
suspended M-VOL, the MCU records the data in the M-VOL tracks that are
updated while the pair is suspended as a differential data, and copies the out-
of-sync tracks to the R-VOL when the pair is resynchronized. If you use an
earlier storage system model than USP V as RCU, the VOLSER is also copied.
• For a suspended TCz Asynchronous pair, the MCU and RCU keep track of any
recordsets that were discarded during suspension, and the MCU continues
accepting write I/Os for the M-VOL. When a TCzA pair is resynchronized, the
MCU merges the M-VOL and R-VOL differential data and then copies the out-
of-sync tracks to the R-VOL to resynchronize the pair. If you use an earlier
storage system model than USP V as RCU, the VOLSER is also copied.
The Resume Pair dialog box (see Figure 6-6) allows you to resynchronize
suspended TCz pairs. To open the Resume Pair dialog box, click the Pair
Operation tab, select a CU grouping or CU from the tree, select the M-VOL(s)
of the pair(s) to be resynchronized, right-click, and then click Resume Pair.
Figure 6-6 Resume Pair Dialog Box