Installation guide

example,. mod_jk, mod_proxy, mod_cluster) is being used for load balancing for this web
application. If set to true, the container will examine the session ID associated with every
request and replace the jvmRoute portion of the session ID if it detects a failover.
You need only set this to false for web applications whose URL cannot be handled by the JK
load balancer.
<max- unreplicate d-int erval>
Specifies the maximum interval between requests, in seconds, after which a request will trigger
replication of the session's timestamp regardless of whether the request has otherwise made
the session dirty. Such replication ensures that other nodes in the cluster are aware of the
most recent value for the session's timestamp and will not incorrectly expire an unreplicated
session upon failover. It also results in correct values for
HttpSession.getLastAccessedTime() calls following failover.
The default value is null (in effect, unspecified). In this case the session manager will use the
presence or absence of a jvmRoute configuration on its enclosing JBoss Web Engine (see
Section 3.2, “Configuring JBoss to work with mod_jk”) to determine whether JK is used.
A value of 0 means the timestamp will be replicated whenever the session is accessed. A value
of -1 means the timestamp will be replicated only if some other activity during the request (for
example,. modifying an attribute) has resulted in other replication work involving the session. A
positive value greater than the HttpSession.getMaxInactiveInterval() value will be
treated as probable misconfiguration and converted to 0; (in effect, replicate the metadata on
every request). Default value is 60.
<snapshot -mode>
Specifies when sessions are replicated to the other nodes. Possible values are INSTANT (the
default) and INTERVAL.
The typical value, INSTANT, replicates changes to the other nodes at the end of requests, using
the request processing thread to perform the replication. In this case, the snapshot-interval
property is ignored.
With INTERVAL mode, a background task is created that runs every snapshot-interval
milliseconds, checking for modified sessions and replicating them.
Note that this property has no effect if replication-granularity is set to FIELD. If it is
FIELD, INSTANT mode will be used.
<snapshot -interval>
Specifies how often (in milliseconds) the background task that replicates modified sessions
should be started for this web application. Only meaningful if snapshot-mode is set to
INTERVAL.
<session-not ification- policy>
Specifies the fully qualified class name of the implementation of the
ClusteredSessionNotificationPolicy interface that should be used to govern whether
servlet specification notifications should be emitted to any registered HttpSessionListener,
HttpSessionAttributeListener and/or HttpSessionBindingListener.
Important
Event notifications that may be appropriate in non-clustered environment may not
necessarily be appropriate in a clustered environment; see
https://jira.jboss.org/jira/browse/JBAS-5778 for an example of why a notification may not
be desired. Configuring an appropriate ClusteredSessionNotificationPolicy gives
the application author fine-grained control over what notifications are issued.
17.2. HttpSession passivation and activation
Passivation
The process of controlling memory usage by removing relatively unused sessions from memory while
storing them in persistent storage.
If a passivated session is requested by a client, it can be "activated" back into memory and removed
from the persistent store. JBoss Enterprise Application Platform 5 supports HttpSession passivation
JBoss Enterprise Application Platform 5 HTTP Connectors Load Balancing Guide 69