One-to-one volume copy operations, Duplicate volser, Logical volume image (lvi) – HP StorageWorks XP Remote Web Console Software User Manual
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Record zero (R0) must be standard format, with key length of zero and data length of eight. The MCU
will abort the initial copy operation if R0 is not standard format.
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The CCHH (logical cylinder address and logical head address) of R0 must be identical to the physical
cylinder address and physical head address of the track.
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The CCHH of each user record in a track must be unique.
One-to-One Volume Copy Operations
TC390 requires a one-to-one relationship between the logical volumes of the volume pairs. A volume can
be assigned only to one TC390 pair at a time. TC390 does not support operations in which one M-VOL is
copied to more than one R-VOL, or more than one M-VOL is copied to one R-VOL. Because TC390 pairs
are created on logical volumes rather than datasets, multivolume datasets require special attention. For
complete duplication and recovery of multivolume datasets, verify that all volumes of a multivolume dataset
are copied to TC390 R-VOLs and use TC390A to ensure update sequence consistency across the R-VOLs at
the remote site.
Duplicate VOLSER
The TC390 initial copy operation always copies the VOLSER of the M-VOL to the R-VOL, even if the No
Copy initial copy option is selected. For this reason, the M-VOL and R-VOL of a TC390 pair must have the
same VOLSER. Because the host operating system does not allow duplicate VOLSERs, the host system
administrator must take precautions to prevent system problems related to duplicate VOLSERs. For example,
the TC390 R-VOLs must be defined in the system generation so they do not come online automatically.
CAUTION:
If the volumes that will become TC390 R-VOLs are physically attached to the same system
images as the production volumes that will become the TC390 M-VOLs, the following problems can occur:
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When a TC390 pair is established using the TSO CESTPAIR command, the secondary volume might be
online. PPRC allows this, but TC390 does not (see the following note). This could produce a duplex
secondary online to a host image, the results of which are not predictable.
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When a TC390 pair is deleted, the old secondary volume is usually offline. If a host image is IPL’d, the
operator will be offered both volumes and asked which volume should be left offline – the old duplicate
volser message. This can be confusing and is prone to error.
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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 XP128/XP1024/XP10000/XP12000
(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 XP128/XP1024/XP10000/XP12000 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.