Introduction to vPartitions

vPars Is a Virtual Partitions product that enables you to run multiple instances of HP-UX simultaneously on one hard partition by dividing that hard partition further into virtual partitions.

Each virtual partition is assigned its own subset of hardware, runs a separate instance of HP-UX, and hosts its own set of applications. Because each instance of HP-UX is isolated from all other instances, vPars provides applicationand Operating System (OS) fault isolation.

Each instance of HP-UX can have different patches and a different kernel .

vPar-Representation

Key Terms of vPar

 

Complex:

A complex is the entire partitionable server, including both cabinets, all cells, I/O chassis, cables, and power and utility components.

Cabinet

A cabinet is the Superdome hardware “box”, which contains the cells, Guardian Service Processor (GSP), internal I/O chassis, I/O fans, cabinet fans, and power supplies. A complex has up to two cabinets.

Hard partition

A hard partition is any isolated hardware environment, such as an nPartition within a Superdome complex or an entire rp7400/N4000 server.

npartition

An nPartition is a subset of a complex that divides the complex into groups of cell boards where each group operates independently of other groups. An nPartition can run a single instance of HP-UX or be further divided into virtual partitions.

Virtual partition

A virtual partition is a software partition of a hard partition that contains an instance of

HP-UX. Though a hard partition can contain multiple virtual partitions, a virtual partition cannot span a hard partition boundary.

vPars Monitor and Database

vPars 

For each hard partition, the vPars Monitor manages the assignment of hardware resources to virtual partitions, boots virtual partitions and their kernels, and emulates certain firmware calls. By emulating these specific calls, vPars creates the illusion to each HP-UX instance that it is running on a standalone server, consisting of the hardware that has been assigned to it.

Once a virtual partition is launched, the Monitor transfers ownership of the hardware to the virtual partition. At that point the Monitor is not involved in accessing I/O hardware, physical memory, or process to processor cycles: the individual HP-UX instances have complete ownership of their respective hardware resources. This allows each partition to run at full speed.

vPars Partition Database

At the heart of the vPars Monitor is the partition database. The partition database contains partition configuration information. Using the partition database, the Monitor tracks which virtual partitions exist and what hardware resources and partition attributes are associated with each partition.

When the Monitor boots , it reads a copy of the partition database from a file on the same disk from which the Monitor /stand/vpmon is booted. The default file is /stand/vpdb. Then, the Monitor creates a master copy of the vPars partition database in the memory reserved by the Monitor.

The operating system of each virtual partition also keeps a local copy of the partition database in a file, by default /stand/vpdb, on its local boot disk

 Boot Sequence

This section describes the boot differences in a vPars system relative to a non-vPars system.

Boot Sequence: Quick Reference

On a server without vPars, a simplified boot sequence is:

 

 

 

vPar-boot-sequence

 

 

Adding vPars adds the Monitor layer, so now hpux (for Integrity, hpux.efi) loads the Monitor.

Then the Monitor boots the kernels of the virtual partitions. The boot sequence becomes

 

 

 

vPar-boot