WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

14.6 z/OS Fast Response Cache Accelerator
This section gives general information about the Fast Response Cache
Accelerator (FRCA).
14.6.1 Overview and benefits
WebSphere Application Server for z/OS V7.0 can be configured to use the Fast
Response Cache Accelerator facility of the z/OS Communications Server
TCP/IP. FRCA has been used for years inside the IBM HTTP Server to cache
static contents like pictures or HTML files.
Attention: This functionality needs z/OS 1.9 or higher to be used. It is not
planned to include this through PTFs in earlier versions of z/OS.
The z/OS Communications Server TCP/IP service updates to the FRCA
support are required for this function to work on z/OS Version 1.9. If the
updated FRCA services are not available on the system, the application
server will issue error message BBOO0347E or BBOO0348E. TCP/IP uses
CSM storage to maintain the cache.
The high speed cache can be used to cache static and dynamic contents, such
as servlets and JavaServer Pages (JSP) files, instead of using the WebSphere
Application Server Dynamic Cache.
Figure 14-10 on page 447 shows the changed flow of a request for a JSP that
can be answered from the cache, assuming that the IBM HTTP server also
resides on z/OS:
► Without FRCA exploitation a request has to be processed by TCP/IP, then by
the IBM HTTP Server on z/OS until WebSphere Application Server itself can
answer the request from its Dynacache.
► With FRCA exploitation a request to a cached JSP is recognized in the
TCP/IP processing and gets answered directly.
The benefits of using the FRCA are a reduced response time and a reduced
CPU cost for the serving of requests, compared to the Dynamic Cache. Tests
have shown that a request served from the FRCA used approximately 8% of the
processor time that the same request consumed in a Dynamic Cache
environment. These advantages come from its structure, because the FRCA
cache can directly serve incoming TCP/IP requests (Figure 14-10 on page 447).
446 WebSphere Application Server V7.0: Concepts, Planning, and Design