In Whidbey you can persist cache into disk like sessions. Now you no need to worry about memory problems when you store lots of items in cache. If the memory is full, it will be automatically moved to cache. Also cache can be retained across appdomain restarts. By default diskcaching is enabled and disk quota per application is set to 2 MB. You can change this setting in .config file. For example,
<?xml version="1.0"?>
<configuration>
<system.web>
<caching>
<outputCache>
<diskCache enabled="true" maxSizePerApp="2" />
</outputCache>
</caching>
</system.web>
</configuration>
You can also enable or disable diskcaching at Page level by setting “diskcacheable“ property in page directive like this,
<%@ OutputCache Duration="3600" VaryByParam="name" DiskCacheable="true" %>