HP-UX Virtual Partitions Administrator Guide (includes A.05.08) (5900-1312, March 2011)

NOTE: Some examples in this chapter may use a non-nPartitionable system where there is no
cell in the hardware path. If using an nPartitionable system you must include the cell in the hardware
path; read “Planning, Installing, and Using vPars with an nPartitionable Server” (page 49).
I/O: Topics
The I/O topics in this section are:
• “I/O: Concepts and Functionality” (page 171)
• “I/O: Adding or Deleting LBAs” (page 173)
• “I/O: Allocation Notes” (page 174)
I/O: Concepts and Functionality
With vPars, you allocate I/O resources at the LBA level.
LBA Local Bus Adapter
SBA System Bus Adapter
System, Cells, SBA, LBA, Devices and Relationships
On a server, an I/O device communicates to the system through the LBA and SBA. The path looks
like Figure 11.
Figure 11 System to I/O Device Relationship
Syste m
Syste m Bus
Adapte r
Local Bus
Adapte r
IO Devic e
This corresponds to the ioscan hardware path output for an I/O device of sba/lba/ ... /device.
A LBA actually owns all the devices attached to it. In the example below, all the I/O devices
attached to LBA 0 are owned by LBA 0, and the hardware paths of those I/O devices begin with
0/0 (sba/lba). (Cells are discussed later and would change the hardware path to cell_ID/sba/lba.)
Figure 12 LBA Owns Multiple I/O Devices
LBA 0Syste m SBA 0
IO Device s
It is at the LBA level where vPars assigns I/O. In the example below, this means that LBA 0 can
be assigned to at most one virtual partition. If LBA 0 is assigned to vparN, it is implied that all I/O
devices attached to LBA 0 are assigned to vparN.
Figure 13 vPars Allocates I/O at the LBA Level
Syste m SBA 0
a LBA
assignabl e
to a vpar
0/0
LBA 0
IO Device s
A SBA has multiple LBAs attached to it; it is a hierarchical relationship. Nevertheless, assignments
in vPars remain at the LBA level, and each LBA can be assigned to a different virtual partition.
NOTE: Regarding syntax and how vPars commands interpret what is specified on the command
line, see “I/O: Allocation Notes” (page 174). Even if there are shortcuts in assigning LBAs, vPars
assigns per LBA.
In the example below, each LBA (shown in brackets) can be assigned to a different virtual partition.
I/O: Topics 171