Cache instance settings
A cache instance is a location, in addition to the default shared
dynamic cache, where any Java 2 platform, Enterprise Edition (J2EE) application
can store, distribute, and share data. The cache instance gives applications
greater flexibility and better tuning of the cache resources. The programming
interface to access this cache instance is called DistributedMap. See the
DistributedMap API documentation in the WebSphere Application Server Javadoc
for more information.
To manage cache instances, click Resources > Cache Instances in
the administrative console.
- Name
- Specifies the required display name for the resource.
- JNDI name
- Specifies the Java Naming and Directory Interface (JNDI) name for
the resource. Use this name when looking up a reference to this cache instance.
The returned object has a DistributedMap type.
- Description
- Specifies a description for the resource. This field is optional.
- Category
- Specifies a category string to classify or group the resource.
This field is optional.
- Cache Size
- Specifies a positive integer for the maximum number of entries
that the cache holds.
The range is 100 to 200,000.
- Default Priority
- Specifies the default priority for servlets that can be cached.
This value determines how long an entry stays in a full cache.
The recommended value is one.
- Enable Disk Offload
- Selecting this option will enable disk offloading.
- Disk Offload Location
- Specifies the directory used for disk offload.
If disk offload location is not specified, the default location, ${WAS_TEMP_DIR}/node/server
name/_dynacache/cache JNDI name will be used. If disk offload
location is specified, the node, server name, and cache instance name are
appended. For example, ${USER_INSTALL_ROOT}/diskoffload generates
the location as ${USER_INSTALL_ROOT}/diskoffload/node/server
name/cache JNDI name. This value is ignored if disk offload
is not enabled.
The default value of the ${WAS_TEMP_DIR} property is ${USER_INSTALL_ROOT}/temp.
If you change the value of the ${WAS_TEMP_DIR} property after starting WebSphere
Application Server, but do not move the disk cache contents to the new location:
- The Application Server creates a new disk cache file at the new disk offload
location.
- If the Flush to disk setting is enabled, all the disk cache content at
the old location is lost when you restart the Application Server
- Additional custom properties (available only when a cache instance
is created)
- Custom properties are available for the flushToDiskOnStop and useListenerContext
instances.
You can define custom properties after you create a cache instance.
- Name
- Specifies the name of the custom property. In this case, the name is either
flushToDiskOnStop or useListenerContext. This field is required.
- Value
- Specify true or false to indicate the value of the custom property. This
field is required.
- Description
- Describes any bounds or values of the custom property. This field is optional.

Using the DistributedMap interface for the dynamic cache
Searchable topic ID:
udyn_cacheinstancescollection
Last updated: Jun 21, 2007 8:07:48 PM CDT
WebSphere Business Integration Server Foundation, Version 5.0.2
http://publib.boulder.ibm.com/infocenter/wasinfo/index.jsp?topic=/com.ibm.wasee.doc/info/ee/ae/udyn_cacheinstancescollection.html