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

Preparing for TrueCopy for z/OS Operations 3-7
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
Logical Volume Image (LVI)
TrueCopy for z/OS supports all basic mainframe LVIs which can be configured
on the USP V (e.g., 3390-3, -3R, -9, -L). TCz does not support multiplatform
volumes (3390-3A/B/C). TCz can copy data between volumes with the same
emulation and capacity (e.g., 3390-3R to 3390-3R), and can also copy from
smaller volumes to larger volumes* (e.g., 3390-3 to 3390-9) of the same
emulation (VTOC expansion must be used). TCz also supports the Virtual
LVI/LUN feature of the USP V, enabling you to establish TCz pairs with
custom-size LVIs as well as standard-size LVIs. When custom-size LVIs are
assigned to TCz pairs, the R-VOL must have the same or larger capacity than
the M-VOL. The TCz software displays the LVI of the M-VOLs and R-VOLs.
*WARNING: If you utilize TCz to copy from a smaller volume to a larger
volume, you will not be able to perform TCz operations in the reverse direction
(from the secondary site to the primary site) after a disaster has occurred and
the secondary site was used for production. If the SUSPEND command is
issued from Business Continuity Manager, you will not be able to use the
Secondary Volume R/W option and Reverse option. This restriction exists
because TCz does not support copying from a larger volume to a smaller
volume. Hitachi strongly recommends that this capability (copying from a
smaller volume to a larger volume) only be used for data migration purposes.
WARNING: If you use a Fujitsu operating system, and utilize TCzA to copy
from a smaller capacity of M-VOL to the larger capacity of R-VOL, an error will
occur when the write operation will be performed to the former R-VOL after
the pair has been released. If the write operation is required on this volume,
make the capacity of M-VOL and R-VOL same, and then create a pair.