This section discusses the operational restrictions for
the fast response cache accelerator (FRCA). FRCA is also known as
Adaptive Fast Path Architecture (AFPA).
The following operational restrictions apply:
- When FRCA is enabled, the default value of 0 for the MaxRequestsPerChild
directive should be used, because graceful server restart is not supported
with the cache accelerator.
- FRCA does not support Windows 64-bit
operating systems.
- FRCA cannot be used when certain antivirus software is enabled.
Currently Norton Antivirus has been identified as one such program.
- FRCA access log entries are not integrated with the Apache access
log.
- Only access logging facilities exist for monitoring FRCA.
- On a given machine, only one instance of the IBM® HTTP Server can have FRCA enabled.
- Do not install the IBM HTTP
Server on a machine running the IBM Netfinity® Web Server Accelerator.
- FRCA does not support IPv6.
- FRCA must not be used with locally-mounted network file systems,
such as Network File System (NFS) or Windows shared
drives.
- On Windows systems, AFPA
cannot be loaded if using the Win32DisableAcceptEx directive
- FRCA is not supported on Windows Vista, Windows 2008, or any later Windows operating systems.
- FRCA on AIX® is only supported
with the 32-bit installation of IBM HTTP
Server.
Due to these operational restrictions, and since FRCA/AFPA was
deprecated starting in V7.0, its use is discouraged. Instead, it is
recommended to use the IBM HTTP
Server default configuration to serve static files. This configuration
provides support for features not available with FRCA/AFPA usage,
such as IPv6, SSL, Authentication and access-control, custom headers
and compression.
If CPU usage with the default configuration is too high, the mod_mem_cache
module can be configured to cache frequently accessed files in memory,
or multiple web servers can be used to scale out horizontally. Additional
options include the offloading of static files to a Content Delivery
Network (CDN) or caching HTTP appliance, or to use the caching proxy
component of WebSphere® Edge
Server in WebSphere Application
Server Network Deployment (ND).