Host I/O Time Stamp; Planning Pair Volumes; Data And Journal Volume Specifications - HP StorageWorks P9000 User Manual

Journal volumes consist of two areas: one area is used for storing journal data, and the other
area is used for storing metadata.
Journal volumes support all RAID configurations that are supported by P9500. Journal volumes
also support all physical volumes that are supported by P9500.
Customized volumes can be used for journal volumes.
See "Calculating maximum number of pairs" (page 30)
capacity of journal volumes.
See system requirements and specifications in
more information.

Host I/O time stamp

The I/O time stamping function must be installed on the host processor at the primary site in order
to provide data consistency in Continuous Access Journal Z journals. The I/O time stamp, which
is provided by MVS DFSMSdfp, is the same time stamp that is used by Compatible XRC pairs. The
I/O time stamping function should also be installed on the host processor at the secondary site,
so that time stamps can be used when copying data in the reverse direction.
If the system at the primary and/or secondary site consists of several CPU complexes, a SYSPLEX
timer is required to provide a common time reference for the I/O time stamping function.

Planning pair volumes

The following information is provided to help you prepare volumes for configuration. Also, see
system requirements and specifications in
information.
The emulation and capacity for the S-VOL must be the same as the P-VOL.
When the S-VOL is connected to the same host as the P-VOL, the S-VOL must be defined to
remain offline.
The following CU emulation types can be used for MCUs (primary systems) and RCUs
(secondary systems): 2105, 2107.
The CU emulation type 2105, or 2107 is required for SMS I/O time stamping of Continuous
Access Journal Z journals. When one of these CU emulation types is used, volumes of most
3380 emulation types must not be used. Only 3380-3 can be used.
Continuous Access Journal Z supports the Virtual LVI feature, which allows you to configure
custom-size LDEVs that are smaller than standard-size LDEVs. When custom-size LDEVs are
assigned to a Continuous Access Journal Z pair, the S-VOL must have the same capacity as
the P-VOL. For details about Virtual LVI feature, see HP StorageWorks P9000 Provisioning for
Mainframe Systems User Guide.
Identify the volumes that will become the P-VOLs and S-VOLs.
You can create multiple pairs at the same time. For details, see
When you create a Continuous Access Journal Z pair, you will have the option to create only
the relationship, without copying data from primary to secondary volumes. You can use this
option only when the contents of the primary and secondary data volume are completely the
same.

Data and journal volume specifications

The following table shows maximum capacities and volume types that can be used for data volumes
and journal volumes.
28 Planning volumes, systems
for maximum and minimum supported
"Requirements and specifications" (page 17)
"Requirements and specifications" (page 17) for more
"Pair operations" (page
for
67).