Cost-Effective High-Availability Solutions with HP Instant Capacity on HP-UX

Introduction
Most enterprises today depend on mission-critical applications to run their businesses. Traditionally,
mission-critical applications require high levels of availability, which has proven expensive because of
the need for redundancy, particularly for standby servers. Today, IT managers are challenged by the
need to reduce budgets while still delivering services needed to run the business. HP understands this
problem and has developed products that make high availability more cost-effective.
The key to meeting the need is virtualization—pooling and sharing of resources so that supply meets
demand optimally and automatically. Instant Capacity (iCAP) is a component of the HP Virtual Server
Environment (VSE) that has several features that can reduce the cost of high availability. The newest
addition to the iCAP program, Global Instant Capacity (GiCAP), offers improved flexibility and
utilization of your existing resources. In addition, mission-critical and business-critical applications
often require high availability (HA) to maintain service-level objectives (SLOs). Using iCAP with the
HP Serviceguard suite of high availability solutions can help customers maximize server resource
utilization and reduce the total cost of ownership while providing protection for their applications.
This paper illustrates how iCAP can provide cost-effective, business-continuity solutions. This paper
also provides an overview of HP Serviceguard and a description of traditional high-availability
solutions and configurations, as well as how to use iCAP and Serviceguard together. Some
knowledge of HP Serviceguard and iCAP is helpful, but not required.
Unless otherwise specified in this document, “server” refers to any mid-range or high-end (cell-based)
HP Integrity or HP 9000 server, and “partition” refers to either a hard partition of the server
(nPartition) or a virtual partition (vPar) within the hard partition.
Instant Capacity program overview
iCAP enables customers to quickly adjust processing capacity (cores, cells, and memory) to meet
varying system demands. It can be used to:
Load balance during periods of high utilization
Quickly replace processing capacity lost because of hardware failures
Increase capacity temporarily during periods of high utilization
The HP Instant Capacity program includes three distinct functional areas:
iCAP for processor cores and cell boards with memory: Enables you to deactivate under-utilized
resources in one partition and then, activate unused resources in another partition to alleviate high
resource demand in that partition.
The purchase of each Instant Capacity processor includes an amount of temporary capacity known
as Instant Access Capacity, or IAC.
Temporary Instant Capacity (TiCAP): Enables the temporary activation of additional core resources
when there are no underutilized cores elsewhere on a server that can be deactivated.
TiCAP is optional and can only be utilized in an environment that includes some iCAP components.
Global Instant Capacity (GiCAP): Enables the activation of additional resources on one member of a
GiCAP group after the deactivation of resources on a different member of the group.
GiCAP provides iCAP across multiple servers, including the ability to pool TiCAP usage. GiCAP is
optional and can only be utilized in an environment that includes some iCAP components.
Each type of Instant Capacity provides different opportunities for high-availability solutions, as
discussed later in this paper.
3