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

48 TrueCopy for the XP1024/XP128/XP12000/XP10000
• To avoid these problems, HP strongly recommends that the user specify OFFLINE=YES if the secondary
volumes are to be generated in the production host’s IOCP and system generation.
NOTE: If you cannot create a pair because the TC390 R-VOL is online with hosts, all paths must be offline
from all hosts. If you cannot identify the hosts that are online, please contact your HP account support
representative.
Logical Volume Image (LVI)
TC390 supports basic mainframe LVIs that can be configured on the XP1024/XP128/XP12000/XP10000
(for example, 3390-3, -3R, -9, or -L). TC390 does not support multiplatform volumes (3390-1, -2, -3A/B/C,
3380-K, -E, -J, or -KA/B/C). TC390 can copy data between volumes with the same emulation and
capacity (for example, 3390-3R to 3390-3R), and can also copy from smaller volumes to larger volumes
(for example, 3390-3 to 3390-3R) of the same emulation (VTOC expansion must be used). TC390 also
supports the Virtual LVI/LUN feature of the XP1024/XP128/XP12000/XP10000 to establish TC390 pairs
with custom-size LVIs as well as standard-size LVIs. When custom-size LVIs are assigned to TC390 pairs, the
R-VOL must have the same or larger capacity than the M-VOL. TC390 displays the LVI of the M-VOLs and
R-VOLs.
NOTE: The host I/O time-stamping function is not supported by 3380 LVIs. If you plan to use TC390A
pairs, the TC390A M-VOLs and R-VOLs must be 3390 LVIs.
In the case that M-VOL or R-VOL is 3390-L LVI under the connection of the disk array, and the number of
cylinders is more than 10,017, the capacity of the M-VOL and R-VOL must be the same.
CAUTION: If you use TC390 to copy from a smaller volume to a larger volume, you will not be able to
perform TC390 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. This restriction exists because
TC390 does not support copying from a larger volume to a smaller volume. HP strongly recommends that
this capability (copying from a smaller volume to a larger volume) only be used for data migration
purposes.
CAUTION: If you use a Fujitsu operating system, and utilize TC390A 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 deleted. If the write operation is required on this volume, make the
capacity of M-VOL and R-VOL same, and then create a pair.
Accessing TrueCopy M-VOLs and R-VOLs
Write operations to a TC390 M-VOL that specify normal authorization are duplicated on the R-VOL of the
TC390 pair. Write operations with diagnostic or device support authorization, such as ICKDSF, are
completed at the M-VOL but are not duplicated at the R-VOL. Therefore, you must suspend a TC390 volume
pair before performing ICKDSF media maintenance on the M-VOL. For instructions on running ICKDSF on
TC390 volumes, see ”ICKDSF Considerations for TrueCopy Volumes” on page 136.
To ensure maximum data integrity during normal TC390 operations, the RCU rejects all read and write
operations issued by a host to a TC390 R-VOL. If you need read-only access to a TC390 R-VOL, you must
have the R-VOL read option (see ”R-VOL Read Option” on page 29) enabled on the RCU and you must
suspend the pair to read the R-VOL. The R-VOL read option can be enabled by the HP representative only.
If you need write access to a TC390 R-VOL (for example, to perform ICKDSF), you must delete the pair from
the RCU to change the R-VOL pair status to simplex. For instructions on running ICKDSF on TC390 volumes,
see ”ICKDSF Considerations for TrueCopy Volumes” on page 136.