IBM FileNet P8, Version 5.2.1            

Content cache areas

A content cache area contains frequently accessed document content that was duplicated from the original content that resides in storage areas. Typically, a cache delivers content to users who are in the same local area network (LAN) as the cache. The purpose of a cache is to expedite access to the document content of any geographically remote or slow-to-access storage areas.

If the original content is encrypted, the cache copy of that content is also encrypted. (The original content might be encrypted if you enabled content encryption for the storage area.)

In the administration console, you can configure the following cache attributes:
Content cache area assignment
A content cache can be assigned to one of the following owner objects within the site hierarchy (listed from highest to lowest level): domain, site, virtual server, or server instance. For best results, assign a content cache area to a site. The assignment determines the servers that use the cache: a server finds the lowest-level site hierarchy owner that both the server and a cache belong. For more information about assigning a cache to a site hierarchy object, see Assigning a content cache area.
Storage areas that are serviced
The level of caching permitted for a storage area is set independently of the cache area assignment and is not affected by that assignment. The storage area configuration has a property for content caching that can have one of the following values:
Not Allowed
Content from this storage area is never cached in a cache area.
Cross site only
Content from this storage area is cached only in content cache areas that are assigned to a site that is different from the storage area site.
Allowed
Content from this storage area is cached if a content cache area is assigned to the same site as the storage area or for content cache areas that are assigned to different sites than the storage area.
Cache size
A cache can automatically purge content that was not accessed recently.
Content preloading
A cache can automatically load the content of a document when the document is checked in.

Pruning

Pruning is the activity of deleting content files that were not accessed recently. The purpose of pruning is to ensure that the cache is the minimum size necessary to store the most recently accessed content.

Two types of pruning operations can occur:
Periodic pruning (triggered by the Maximum Time To Live property)
Periodic pruning removes content files that were not accessed for a longer time than the time allowed by the Maximum Time To Live property. (Document content that is accessed frequently enough can remain in cache indefinitely.) The pruning occurs automatically halfway through the period that is specified by the Maximum Time To Live property.
Mandatory pruning (triggered by the Prune Threshold Size KBytes property or Prune Threshold Content Elements property)
Mandatory pruning removes content files in least-recently accessed order until the total number and size of the remaining files does not exceed some calculated target total. The target total calculation involves a property that specifies the percentage to prune (Prune Amount) and the following threshold properties: Prune Threshold Size KBytes and Prune Threshold Content Elements. The pruning occurs automatically when the number or size of the content files exceeds one of these thresholds.

Content cache area management

Important: Disable content caching for storage areas that contain confidential or sensitive documents. The deletion of content in a storage area does not delete the copied content in a cache area. Confidential or sensitive content in a cache can remain accessible to users after the deletion of the original content from a storage area.
The following content cache configuration guidelines can help improve your system performance:
Assign content cache to the same site in which it is created.

Create the content cache area in a site where it can be accessed by the Content Platform Engine servers in that site over a high-speed network, then assign the content cache area to that same site. Avoid assigning a content cache area from a different site that is accessed remotely over a slow-speed network.

If you must administer a remote content cache, the Content Platform Engine administration console must be able to directly access the content cache, such as through Content Platform Engine to Content Platform Engine communication. If server communication is not available, use the administration console in the remote site to manage the content cache.

Use cache directory for caching.
Do not store documents in a directory that is designated as a content cache area. Storing other documents in that directory uses space that is required for content caching.
Optimize pruning threshold by using the Prune Threshold Size KBytes property.
Set the Prune Threshold Size KBytes property to optimize system performance. If the content cache server has a large hard disk, you can afford to enlarge the maximum space for content caching. Doing so minimizes network traffic and reduces network access time by keeping the most recently accessed content in local cache. If your caching server has limited space available, reduce the maximum space for content caching. Allocating more space than the server has available can tie up system resources and slow down system performance.
Optimize pruning threshold by using the Prune Threshold Content Elements property.
Determine the number of files that are frequently accessed by users. Increase that number by 5-10% to determine the maximum number of files that are allowed in the cache. If your system maintains relatively small files, you can allow a greater number of files in cache.
Preload accessed content only.
Do not enable the Preload On Create option when the associated site is used heavily to create documents that are not retrieved later.
Adjust Maximum Time To Live property.
Review your system requirements before you set the Maximum Time To Live interval. The shorter the lifespan is, the more often content is removed and refetched. The longer the lifespan is, the more deleted content occupies the content cache area.
Periodically review cache properties.
Analyze the content cache settings periodically and modify the configuration properties as necessary. For example, you might experience a system slowdown if users access more files than the configured threshold permits for the content cache area. In this case, increase the maximum number of files allowed.
Make the cache accessible to servers.

Make a content cache area accessible from every Content Platform Engine server in its same site and to other sites that are assigned to that cache area. It is not necessary for a cache area's root directory to be accessible from other sites that contain their own cache area or from the object store site.

The information that is displayed by the administration console depends on the server to which the administration console is connected. No cache area statistics are displayed if the Content Platform Engine server cannot access the root path of the cache area.

Restriction: Administration of a content cache area requires access to that area on the file system. You can create a new cache only through a server that has access to the root path.


Last updated: March 2016
cs_about_content_cache_stores.htm

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