Network Server Accelerator HTTP Performance White Paper November 2002 Manufacturing Part Number: NSAWP-90902 © Copyright 2002 Hewlett-Packard.
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Network Server Accelerator HTTP Performance Introduction Network Server Accelerator HTTP Performance Introduction As the demand for faster and more scalable web service increases, computer system designers have discovered ways to improve web server performance and scalability by integrating web server functionality into operating systems. This trend began with system designers adding system interfaces specifically designed for web servers.
Network Server Accelerator HTTP Performance NSA HTTP Product Description 1. Connection management 2. Streams caching 3. Mechanism to forward requests it cannot satisfy (such as requests for data not in the cache) to the user space application The HTTP-specific portion of NSA HTTP consists of the following components: 1. HTTP data cache 2. HTTP protocol processing routines The HTTP-specific portion of NSA HTTP is implemented as a DLKM module.
Network Server Accelerator HTTP Performance Deployment Scenarios Deployment Scenarios There are a number of ways NSA HTTP can be deployed. We briefly describe two scenarios to highlight the most typical deployments. The simplest scenario uses NSA HTTP and a conventional user-level web-server process co-located on a single system (Figure 1). In this topology, NSA HTTP increases server capacity by increasing the efficiency for processing static requests.
Network Server Accelerator HTTP Performance Deployment Scenarios Manually partitioning the content of a site requires not only distributing specific content types to the appropriate servers, but also modifying HTML pages that refer to the content to identify the server for each item delivered by a specialized server. Therefore, administrators may be reluctant, unwilling, or unable to manually partition content for a site after it is operational.
Network Server Accelerator HTTP Performance Performance Tuning Performance Tuning NSA HTTP Tuning This section describes the NSA HTTP operating parameters that you can tune to improve performance. Maximum NSA HTTP Cache Percentage (max cache percentage) The maximum NSA HTTP URI (Uniform Resource Identifier, a term that encompasses URL) cache size is configured as a percentage of system memory. You can set the value for this parameter by editing /etc/rc.config.
Network Server Accelerator HTTP Performance Performance Data Conversely, if you allocate too much memory for the NSA HTTP URI cache, there may not be sufficient memory for the file system buffer cache. This may cause file system performance to degrade, including performance for sendfile() operations. The sendfile() routine transmits files over a network connection directly from the file system buffer cache. Some web servers use sendfile() to service static content requests.
Network Server Accelerator HTTP Performance Conclusion Conclusion NSA HTTP will improve performance for static web pages. It also provides a framework on which future HTTP performance improvements can be made. The generic framework can also be used to make performance improvement for other network servers (like FTP, streaming video, etc).
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