From the Session Name list, select a session to enable binding for a specific

Configuring High Availability Solutions 3-13 Web Cache. In addition, the respective passwords for the Oracle Web Cache administrator, and the invalidator user, invalidator, must be the same across the cluster members. If they are different, you must connect to the caches admin server and modify the administration password, as described in Section 5.2 .

3.6.2 Understanding Failover Threshold and Capacity Settings

To ease with configuration, take the time to understand the following key configuration settings for a cache cluster and its members: ■ Section 3.6.2.1, Failover Threshold for the Cache Cluster ■ Section 3.6.2.2, Capacity for Cache Cluster Members

3.6.2.1 Failover Threshold for the Cache Cluster

You set the failover threshold when you configure cache cluster properties. This setting reflects the number of allowed consecutive request failures before Oracle Web Cache considers another cache cluster member to have failed. In other words, Oracle Web Cache consecutively retries a failed member for certain number of times, before considering the cache-member as down. The number of times Oracle Web Cache is allowed to retry is termed as failover threshold. Oracle Web Cache considers a request to another cache cluster member to have failed if: ■ There are any network errors ■ The HTTP response status code is 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, or 504 Gateway Timeout, or less than 100. For each failed request, Oracle Web Cache increments the failure counter for that cluster member. This counter is kept separately by each cluster member. When a request is successfully processed by a cluster member, Oracle Web Cache resets the failure counter. When the failover threshold is met, Oracle Web Cache considers the cache cluster member to have failed. Oracle Web Cache recalculates the relative capacity of the remaining cache cluster members. It then reassigns ownership of cache content. When a cache cluster member is down, Oracle Web Cache starts polling the cache cluster member. It does this by sending requests to the ping URL you specify. When Oracle Web Cache receives a success response from the cache cluster member, it considers that cache cluster member to be up again. It recalculates the relative capacity of the cache cluster members and it reassigns ownership of cache content.

3.6.2.2 Capacity for Cache Cluster Members

When you configure a cache cluster member, you specify capacity for that member. Oracle Web Cache uses capacity in two different ways: ■ As the absolute capacity for the number of concurrent incoming connections to this cache cluster member from all other cache cluster members. The connections are used to receive requests for owned content from other cache cluster members. The number of connections are divided among the other cluster members. For example, in a three-cache cluster, if the capacity of Cache_A is 50, Cache_B can open 25 connections to Cache_A and Cache_C can open 25 connections to Cache_A.