Use this page to set Java virtual machine (JVM) custom properties to maintain cache entries that are saved to disk.
You can set the custom properties globally to affect all cache instances, or you can set the custom property on a single cache instance. In most cases, set the properties on the individual cache instances. To set the custom properties on the default cache instance, use the global option. If you set the same property both globally and on a cache instance, the value that is set on the cache instance overrides the global value.
To configure the custom properties on a single object cache instance or servlet cache instance, perform the following steps:
To configure the custom property globally across all configured cache instances, perform the following steps:
Also use these properties to tune the delay offload function for the disk cache.
The delay offload function uses extra memory buffers for dependency IDs and templates to delay the disk offload and minimize the input and output operations. However, if most of your cache IDs are longer than 100 bytes, the delay offload function might use too much memory. Use any combination of the following properties to tune your configuration:
Use this custom property when the flush-to-disk-on-stop feature is enabled. When the server is stopping, offloads are limited to the value specified for this property, pending removal of entries in the explicit invalidation buffer.
Use this property to change the amount of time between disk cache cleanup.
By default, the disk cache cleanup is scheduled to run at midnight to remove expired cache entries and cache entries that have not been accessed in the past 24 hours. However, if you have thousands of cache entries that might expire within one or two hours, the files that are in the disk cache can grow large and become unmanageable. Use the com.ibm.ws.cache.CacheConfig.htodCleanupFrequency custom property to change the time interval between disk cache cleanup.
Units | minutes For example, a value of 60 means 60 minutes between each disk cache cleanup. |
Default | 0 The disk cache cleanup occurs at midnight every 24 hours. |
Use this property to specify the number of different cache IDs that can be saved in memory for the dependency ID and template buffers. Consider increasing this value if you have a lot of memory in your server and you want to increase the performance of your disk cache.
Units | number of cache IDs For example, a value of 1000 means that each dependency ID or template ID can have up to 1000 different cache IDs in memory. |
Default | 1000 |
Minimum | 100 |
Use this custom property to set the percentage of the memory cache size to be used as an overflow buffer when disk offload is enabled.
Cache entries in the overflow buffer are purged and asynchronously offloaded to disk at a frequency of lruToDiskTriggerTime milliseconds. If the memory overflow buffer is full, cache entries are offloaded to disk synchronously on the thread for the caller.
Units | integer, percentage |
Lower bound | 0 |
Upper bound | 100 |
Scope | Configurable per cache instance. |
Use this custom property to set the frequency with which cache entries in memory are asynchronously offloaded to disk when the disk offload feature is enabled.
Units | integer, milliseconds |
Lower bound | 0 |
Upper bound | 5000 |
Scope | Applicable to all cache instances. |