IBM BS029ML - WebSphere Portal Server Self Help Manual page 171

Caches may also be shared among all users or maintained on an individual user basis. As
this can effect the legitimacy of the caches, we do not recommend modifying the sharing
scope of any of the default cache instances.
Clustered Portal environments can on occasion experience cache synchronization issues if
the Dynamic Cache Replication Service (DRS) is not implemented.
This typically manifests itself when modifications are made by the Portal Administrator, such
as a resource ACL change, with the changes not immediately appearing to be propagated to
all the servers participating in the Portal cluster. Under such circumstances, caches are stale
and invalid, until they explicitly expire (dependant on each cache's lifetime setting). Restarting
the entire cluster or individual cluster members in turn can temporarily overcome this difficulty.
However, this should not be considered the fix for the root cause of the problem.
Note: You must enable the DRS in your clustered environment in order to correctly validate
the Portal caches. If DRS is not enabled, situations may arise where users have different
views or different access control rights (ACLs), depending on which cluster member
handles the user's request. It is, however, usual that session affinity is maintained to a
specific cluster member for the life of the user's session. The only exception to this is
failover. The issue is also dependant on the level of Portal Personalization offered to a user.
As all caches eventually expire, you may accept that a stale cache is an anticipated
occurrence and choose to live with the situation. Consult the Information Center for additional
parameters that can be modified.
Configuration Service
Several attributes that influence Portal performance are defined under the Configuration
Service. Among the most important settings are the persistent session options that offer an
authenticated portal user the ability to return to their last visited page from the time of their
last session. However, there is a significant impact in enabling this functionality, as the state
must be persisted to the Portal database. In most cases, disabling this feature is acceptable,
as Portal navigation is more than intuitive for a user. The Configuration Service also holds the
configuration properties for Web Services for Remote Portlets (WSRP) services. shows the
default and recommended values for the Configuration Service.
Table 5-18 Configuration Service
Parameter
persistent.session.level
persistent.session.option
timeout.resume.session
Consult the Information Center for additional parameters that can be modified.
Deployment Service
Although not strictly related to Portal performance, the Deployment Service contains several
important properties. If Portal is deployed in a cluster, then the was.notification.timeout (in
seconds) can be increased to extend the period of time the underlying WebSphere
Application Server will wait before timing out from performing the deployment task of any new
portlets (worst case scenario). This value may have to be increased for large scale Portal
Default value Recommended value
0 May need to be changed. See
InfoCenter.
0 May need to be changed. See
InfoCenter.
false May need to be changed. See
InfoCenter.
Chapter 5. WebSphere Portal runtime and services
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