HP WebQoS Peak for HP-UX Concepts and Operation Guide

Chapter 5 59
HP WebQoS Peak for the Apache Web Server
Integrating HP WebQoS with the Apache Web Server
of six shares.) This amounts to assigning 17% of system resources to A
(1 / 6 * 1), 33% to B (1 / 6 * 2) and 50% to C (1 / 6 * 3).
The assigned share of system resources is used to compute the actual
priority threshold for each virtual host from the server-wide priority
threshold. You can set the value for the server-wide priority threshold
with HPACAdmitPriorityThreshold. The default for this directive is
“0.9.”. For example, to set the server-wide priority threshold to .75, use
the following directive in your configuration file:
HPACAdmitPriorityThreshold 0.75
The setting above will allow up to 75% of all sessions to be priority
sessions. Beyond this threshold, even priority sessions are rejected. The
value set with directive is used to compute the priority threshold for
individual hosts, taking into account the assigned share (see
HPACShareUnits above).
The assigned share is also used to give priority to under-represented
virtual hosts, when virtual host isolation is in effect. Virtual host
isolation is turned on with the HPACVHostIsolation directive. The
default for this directive is “off.” For example, to turn on virtual host
isolation, use the following directive in your configuration file:
HPWebQoSVHostIsolation on
With this option in effect, HP WebQoS raises the priority of new sessions
for those virtual hosts that contribute less than their assigned share to
the system load.
Global Parameters Most HP WebQoS configuration directives set
values for parameters that affect individual virtual hosts. A few of them
set values for parameters that affect all virtual hosts. These directives
are:
The directives setting global HP WebQoS parameters should be used
outside virtual host configuration blocks. Inside virtual host
configuration blocks, the directives are ignored and the parameters they
HPACAdmitPriorityThreshold HPACStatsLogfile
HPACIsolateDamping HPACStatsLogging
HPACLoadDamping HPACVHostIsolation
HPACLogUpdateInterval