Configuring and Migrating Memory on vPars

2
Introduction
Virtual Partitions (vPars) is a feature on HP-UX 11i based systems that allows a system administrator to
divide the hardware resources on a single L-class, N-class, and cellular-based hard partition into one
or more logical partitions. This is accomplished through a software layer called the vPars monitor that
resides between the operating system kernel and the firmware. The vPars monitor controls the
ownership of the processors, memory, and I/O resources on the system. For each partition to be
minimally operational, it must contain at least one processor, enough memory to boot and run HP-UX,
and one or more I/O cards connected to storage and LAN. Each partition runs its own copy of the
operating system thereby providing namespace and software fault isolation.
The system administrator can specify the resources for each partition using a command-level interface.
This partitioning information is stored in a file and that file is commonly referred to as the vPars
database. During system boot, the vPars monitor takes inventory of the resources on the system, reads
the vPars database, and assigns the available resources to the defined partitions according to the
partition plan stored in the vPars database. When each partition is launched, the operating system
calls firmware to discover the subset of the system resources it owns. The vPars monitor, with help
from firmware, exposes to each partition’s kernel only those processors, memory, and I/O cards that
the partition owns. Hence, each partition only accesses the subset of resources on the system that it
owns.
The main objective of this document is to describe memory resource configuration in a vPars system
with particular emphasis on memory migration; that is, the ability to dynamically add and delete
memory from partitions. The document describes the various choices available to the user to control
memory assignment to each partition with generic guidelines to follow while using these choices, the
binding of physical memory done by the vPars monitor and the tools available to observe and
validate memory assignment.
The document is intended for system administrators and users of all vPars releases who configure and
manage memory. While perusing this document, users of vPars A.04.xx release can skip the
discussion related to memory migration and users of vPars A.01.xx, A.02.xx and A.03.xx releases
can skip locality and memory migration discussions.
The rest of this document is divided into six chapters:
• The “Memory Categories” chapter describes different memory types available for assignment.
• The “Memory Granules – Containers of Physical Memory” chapter describes the granules,
which are the unit of memory resources available for assignment.
• The “Memory Resource Assignment” chapter describes how monitor assigns memory to each
partition.
• The “User Specified Ranges” chapter describes how user can explicitly control the memory
binding.
• The “Memory Migration Management” chapter describes the tools available to manage
memory migration.
• The “Memory Accounting” chapter details the commands available to the user to check memory
assignment.