Global attributes apply to
all cached data. You can specify the amount of NetScaler memory allocated to
the integrated cache, Via header insertion, a criterion for verifying that a
cached object should be served, the maximum length of a POST body permitted in
the cache, whether to bypass policy evaluation for HTTP GET requests, and an
action to take when a policy cannot be evaluated.
The cache memory capacity
is limited only by the memory of the hardware appliance. Also, any packet
engine (the central distribution hub of all incoming TCP requests) in the nCore
NetScaler appliance is aware of objects cached by other packet engines in the
nCore NetScaler appliance.
Note that the default
global memory limit is 0. Therefore, even if Integrated Caching is enabled, the
NetScaler appliance does not cache any objects. You must explicitly set the
global memory limit when integrated caching is enabled.
You can modify the global
memory limit configured for caching objects. However, when you update the
global memory limit to a value lower than the existing value (for example, from
10 GB to 4 GB), if a higher amount of memory (greater than 4 GB) is already
being used to cache objects, the NetScaler continues using that amount of
This means that even
though the integrated caching limit is configured to some value, the actual
limit used can be higher. This excessive memory is however released when the
objects are removed from cache.
The output of the
cache parameter command indicates the configured value (Memory Usage
limit) and the actual value being used (Memory usage limit (active value)).