Enhydra Director


Table of Contents

1. Release Notes
2. Enhydra Director installation notes
Apache Module
NSAPI Module
IIS Module

Chapter 1. Release Notes

This document contains the release notes for Enhydra Director 5.1final.

  • The problem with the Enhydra director on Windows 2000 (with service pack 3) and Windows XP has been corrected. Now, Windows 2000 (with any version of SP), Windows XP and Windows 2003 are supported.

  • Supports correct IIS log entries for W2K SP3, XP.

  • Added Joao Ribeiro's patch that corrects the behavior of the port restriction of virtual server definition within <Restrict> tag in the enhydra director configuration file. (Enhydra Director mailing list archive, 2003-09-16: Enhydra: Patch for the director "Bug" in virtual host port verifcation).

  • Added support for a simple cache system built in the enhydra director for IIS only. This cache system is designed for caching small object within application pages such as small pictures (gif, jpeg), simple css in oreder to decrease the load of app servers and to provide faster response to the clients.

  • Added basic url-rewrite feature in the enhydra director for IIS only.

NOTE: For more information about building, configuring and tuning Enhydra Director see the more detailed documentation (html, pdf).

Chapter 2.  Enhydra Director installation notes

Apache Module

The Apache implementation of Enhydra Director is an Apache 1.3.x module that is compiled and installed directly into your Apache server. The 'mod_enhydra_director.so' file is the name of the compiled module. Also, due to the design of the Apache server, a daemon program runs and performs housekeeping on a shared memory scoreboard that is used by the httpd child processes to keep track of multiserver connection traffic for load balancing and fail-over purposes. This daemon program is called 'edir_daemon'. A rough and simple debugging utility, 'edir_status' also exists to check the state of the shared memory scoreboard. This utility exists only for Apache because of its shared memory design.

For more information on the Enhydra Director module for Apache, see the Apache (html, pdf) documentation.

NSAPI Module

The Netscape server implementation of Enhydra Director is an NSAPI server extension. This extension is normally compiled and installed on the Netscape Web server following the usual procedures for an NSAPI plugin. Additionally, the standard releases of Enhydra contain pre-built 'DLL' binaries for installation on Microsoft Windows NT or Windows 2000 systems.

Because the Netscape server implements a multithreaded shared memory design, there is no shared memory functionality in the NSAPI plugin, and the 'edir_daemon' and 'edir_status' are not available.

For more information on the Enhydra Director module for NSAPI, see the IPlanet (html, pdf) documentation.

IIS Module

The Microsoft IIS implementation of Enhydra Director consists of both an ISAPI filter DLL and an ISAPI extension DLL. The IIS module only operates on Windows NT or Windows 2000, since those are the platforms supported by IIS. The DLLs can be built from source code using Visual C++ 6.0 or later, or pre-built binaries can be obtained from the Enhydra release.

Because the IIS server implements a multithreaded shared memory design, there is no shared memory functionality in the ISAPI plugins, and the 'edir_daemon' and 'edir_status' are not available.

For more information on the Enhydra Director module for IIS, see the IIS (html, pdf) documentation.