Setup and Install

Understanding HP WebQoS
The Role and Benefits of HP WebQoS
Chapter 1 15
transactions can be completed quickly.
With Capacity Protection, you configure a system when it is functioning
at peak levels to do the following:
• Redirect high priority customers to another system with available
capacity.
• Defer high priority customers for a few moments until current
sessions are completed.
• Reject low priority customers in extreme overload conditions.
Policy Based Service Level Objectives (SLOs) and Thresholds
To ensure that your business policies are reflected in your Web
applications, they need to be translated into service level objectives
(SLOs) and thresholds. SLOs are business-oriented policies and
thresholds are operations-oriented policies.
Business-oriented service level objectives define the following:
• Response time—measured from the time a request enters the server
to the time it leaves the server.
• Concurrent session capacity—created when an initial request is
accepted and maintained until the session times out.
Operations-oriented thresholds for capacity protection determine the
following:
• Average CPU load—measured on the local system.
• Queue depth—the maximum number of service requests waiting that
are not yet forwarded to the web server.
The administrator defines SLOs, thresholds, and their relative priorities.
WebQoS can trade off meeting policies based on these priorities.
Information Technology rules concerning response time, throughput,
availability, and priorities for request classification rules and
applications are translated into SLOs and thresholds.
The administrator also configures corrective actions that are executed
when the rules are violated. Corrective actions are a list of prioritized
actions an administrator uses to help bring the SLO or threshold into
compliance with the rule.