Displaying cache information

Use this task to monitor the activity of the dynamic cache service.

The dynamic cache monitor is an installable web application that displays simple cache statistics, cache entries, and cache policy information for servlet cache instances.

The cache monitor provides information about the cache in the servant to which the browser connects to interact with the monitor. In an environment with multiple servants, the cache monitor provides a partial view of caching activity.

1. Use the administrative console to install the cache monitor application from...
   app_server_root/installableApps/CacheMonitor.ear

   Install the cache monitor onto the application server to monitor.

   Access the cache monitor on the application port, which uses 9080 as its default port number.

   The cache monitor application must be installed on the default_host (908x).

2. Configure the web container transport chain and host alias for the server with cache monitor installed.

   1. Add a host alias for the port the server is using.
      Environment | Virtual hosts | host_type | Host aliases

      Create a new Host name and Port to add to the list. Creating a host alias enables you to access the cache monitor using...

      http://your_host:your_port_number/cachemonitor

   We can find the port number in the SystemOut.log file. Look for message TCPC0001I or SRVE0171I.

3. Access the cache monitor using a web browser and the URL...
   http://yourhost:your port_number/cachemonitor

   where the port_number is the port associated with the host on which you installed the cache monitor application.

4. Verify the list of cache instances that are shown. For each cache instance, we can perform the following actions:

   We must select the servlet cache instance to monitor. If we do not use servlet cache instances by using <cache-instance> tags in the cachespec.xml file, all the content is in the baseCache instance.

   • View the Statistics page and verify the cache configuration and cache data. Click Reset Statistics to reset the counters.

   • View the Cache Policies page to see which cache policies are currently loaded in the dynamic cache. Click a template to view the cache ID rules for the template.

   • View the Cache Contents page to examine the contents that are currently cached in memory.

   • View the Edge Statistics page to view data about the current ESI processors configured for caching. Click Refresh Statistics to see the latest statistics or content from the ESI processors. Click Reset Statistics to reset the counters.

   • View the Disk Offload page to view the disk configuration, statistics, and the content currently off-loaded from memory to disk.

   When viewing contents on memory or disk, click a template to view all entries for that template, click a dependency ID to view all entries for the ID, or click the cache ID to view all the data that is cached for that entry.

5. Use the cache monitor to perform basic operations on data in a cache instance.

   Remove an entry from cache

   Click Invalidate when viewing a cache entry.

   Remove all entries for a certain dependency ID

   Click Invalidate when viewing entries for a dependency ID.

   Remove all entries for a certain template

   Click Invalidate when viewing entries for a template.

   Move an entry to the front of the Least Recently Used queue to avoid eviction

   Click Refresh when viewing a cache entry.

   Move an entry from disk to cache

   Click Send to Memory when viewing a cache entry on disk.

   Clear the entire contents of the cache

   Click Clear Cache while viewing statistics or contents.

   Clear the contents on the ESI processors

   Click Clear Cache while viewing ESI statistics or contents.

   Clear the contents of the disk cache

   Click Clear Disk while viewing disk contents.

Note that IBM also has an Extended Cache Monitor application which you can download and install.

Subtopics

• Cache monitor
  
• Dynamic cache MBean statistics
  
• Dynamic cache PMI counter definitions
  
• Tune dynamic cache with the cache monitor
  

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