HP Mainframe Connectivity Design Guide

Table 54 XP7 PAV support
Maximum number of PAVs per base addressCU typeStorage system
2552107XP7
Multiple allegiance
MA enables multiple LPARs to issue multiple I/O requests in parallel to a disk volume. MA is a
standard part of the PAV feature in the XP7 storage system.
Hyper PAV
Hyper PAVs build on the PAV and MA functions. The difference is that instead of fixed alias
addresses configured for each base address, Hyper PAV allows a pool of alias addresses to be
used and reused to access base addresses. This means that fewer alias addresses need to be
configured because each alias address can be assigned dynamically to a base address as needed.
The IOS in the mainframe manages the Hyper PAV pool, assigning (or binding) an alias address
to a base address for the duration of a single I/O command. After the I/O completes, the alias
address is released, and it can then be bound to another base address when needed.
Table 55 (page 100) lists theXP7 CUs that support Hyper PAV.
Table 55 Hyper PAV support
Maximum number of PAVs per base addressCU typeStorage system
255
1
2107XPZ
1
The actual number required for your workload is typically much less.
XP7 configuration rules
Table 56 (page 100) lists the XP7 mainframe configuration rules.
Table 56 XP7 configuration rules
DescriptionRule
The XP7 storage system must be configured to emulate an IBM CU for mainframe implementations. For
a list of IBM CUs, see Table 50 (page 98).
1
The XP7 storage system must be configured to emulate IBM disk volumes. For a list of IBM volume types,
see Table 50 (page 98).
2
A maximum of 256 disk volumes per CU/LCU is supported.3
The storage system is logically partitioned into uniquely addressable LCUs. Each image appears as an
independent LCU, but all LCUs share a common set of hardware facilities. Each LCU is configured with
a maximum of 256 volumes.
4
Each volume in the LCU is assigned a unique two-digit hexadecimal unit address in the range x'00' to
x'FF'.
5
A combination of the LCU number and the unit/device address uniquely identifies a particular volume
in the storage system.
6
The LCU is called the CUADD in the mainframe configuration file. The CUADD is a two-digit hexadecimal
value in the range x'00' though x'FF'. For example, LCU x'01' is the same as CUADD x'01'.
7
A unique 4-digit hexadecimal device address in the range x'0000' to x'FFFF' is assigned to each volume
in the mainframe configuration. This device address is also referred to as a UCB.
8
A unique 4-digit hexadecimal CUNUMBER in the range x'0000' to x'FFFF' is assigned to each LCU in
the mainframe configuration. Typically, the starting device address or UCB is assigned as the CU number.
9
100 XP7 storage system rules