Configuring Oracle Web Cache for Scalability and Failover

Purpose

This tutorial describes how to add an instance of Oracle Web Cache to a cluster and propagate changes.

To increase the availability and scalability of your Web site, you can configure multiple instances of Oracle Web Cache to run as members of a cache cluster. The cluster members share common configuration characteristics and content ownership. A significant benefit of this feature is that the cluster members are capable of failure detection. A cache cluster can contain two or more instances of Oracle Web Cache, and so you must have two or more instances of Oracle Web Cache installed on a single machine or multiple machines before you configure a cache cluster. For load balancing options, refer to the Oracle Fusion Middleware Administrator's Guide for Oracle Web Cache 11g Release 1 (11.1).

Software and Hardware Requirements (Optional)

The following is a list of software requirements:

Item	Specification
Processor Type	Intel Xeon or Pentium IV
Processor Speed	2.4 GHz or higher
Number of Processors	1 or more (if required)
Memory	2 GB
Hard Disk Space	20 GB (initial size)
Operating System	RedHat Enterprise Linux 4 Update 5

Prerequisites

Before starting this tutorial, you should:

.	Have an instance of Oracle WebLogic Server 10.3
.	Have configured a domain
.	Have completed the OBE titled "Configuring Oracle Web Cache for Caching a JavaEE Application"
.	Have completed the OBE titled "Configuring Oracle Web Cache for Session Binding and Load Balancing"

Adding a Cluster Member

To add an instance of Oracle Web Cache to a cluster, perform the following steps:

Navigate to the Web Cache Home page in Fusion Middleware Control for an
Oracle Web Cache instance.

From the Web Cache menu, select Administration and then select Cluster.
The Cluster page displays.

Click Add to add a cluster member.

Verify the following values for the corresponding fields and then click Apply:

Parameter	Value
Component Name	Select the name of the cache member
Capacity	30 (default value)
Invalidation requests sent to any cluster member will be propagated to all cluster members	Checked
Failover Threshold	5 (default value). This is the number of allowed consecutive request failures before Oracle Web Cache considers another cache cluster member to have failed. The default is five failures.
Ping URL	_oracle_http_server_webcache_static_.html (default value). This is the URL that cache cluster members uses to attempt to contact a cache cluster member that has reached its failover threshold.
Ping Frequency (seconds)	10 (default value). This is the time in seconds, between attempts by a cluster member to reach the failed cluster member.

Click Web Cache > Control > Restart to restart Oracle Web Cache.

Click Restart to confirm.

Click Close when the restart operation completes successfully.

Propagating Configuration Changes

When you modify the cluster and apply changes, Oracle Web Cache adds the cache-specific information from the new cache cluster members to the configuration. For those changes to take effect in all cluster members, you must propagate the configuration and restart the cache server process of the cluster members. To propagate configuration changes, perform the following steps:

.	From Web Cache menu > Administration > Cluster page, select the other cache member in the cluster. Click Synchronize.
.	Click Yes to confirm the operation.
.	Select the second cache member and click Restart. Click Yes to confirm.
.	Select the first cache member and click Restart. Click Yes to confirm. The cache cluster is ready to use.