Webserver Stress Tool

By simulating the HTTP requests generated by hundreds or even thousands of simultaneous users, you can test your web server performance under normal and excessive loads to ensure that critical information and services are available at speeds your end-users expect.

Detailed test logs and several easy to read graphs make analyzing results a snap. Webserver Stress Tool for Windows (2000/XP/2003/Vista) can benchmark almost any HTTP server (e.g. static pages, JSPs/ASPs, or CGIs) for performance, load, and stress-tests.

Using Webserver Stress Tool when developing and running Websites is important for your web infrastructure:

• Maximize Uptime: Resolve performance critical issues in your webserver before they bring down your website
• Maximize Performance: Make sure that your websites and applications are given the server resources they need when they need it to guarantee a high quality user experience
• Maximize ROI: Get everything out of the investment in your webserver technology through consistent and in-depth testing and analysis
• Maximize Value: Webserver Stress Tool is the most cost-effective solution in the market for simulating performance, load, and stress tests for your web server
• Minimize Efforts: The software installs in 5 minutes and works with all web servers

Webserver Stress Tool simulates large numbers of users accessing a website via HTTP/HTTPS. The software can simulate up to 10.000 users that independently click their way through a set of URLs. Simple URL patterns are supported as well as complex URL patterns (via a Script file).

Webserver Stress Tool simulates independent users stepping through a set of URLs or through URLs that you can specify using a VB script. Based on parameters you specify, the application not only requests the HTML of a URL but also frames, images, flash files, etc. emulating the same behaviour a web browser would show when accessing the website.

Each user is simulated by a separate thread with his own session information (i.e., cookies for each simulated user are stored separately) and "surfs" the URLs independently from the other users – just like in real-world Web usage.
URLs can be parameterized for each user and the sequence of URLs can be varied. POST and GET requests are supported as well as BASIC HTTP Authentication and several other settings. With the new scripting functionality you can even create highly complex URL patterns for large scale web applications.

How much load can Webserver Stress Tool generate?

• We have successfully tested Webserver Stress Tool with:
  • more than 500 MBit/s network load
  • more than 1.000.000 pageviews per hour and
  • up to 10.000 simultaneous users

See our Sample Performance Tests section for more detailed test reports. The actual load you can achieve is highly dependent on your network infrastructure, your server/client hardware, the file sizes and your web application.

Supported Test Types

• Webserver Stress Tool supports a number of different testing types. For example:
• Performance Tests—this test queries single URLs of a webserver or web application to identify and discover elements that may be responsible for slower than expected performance. This test provides a unique opportunity to optimize server settings or application configurations by testing various implementations of single web pages/script to identify the fastest code or settings.
• Load Tests—this tests your entire website at the normal (expected) load. For load testing you simply enter the URLs, the number of users, and the time between clicks of your website traffic. This is a “real world” test.
• Stress Tests—these are simulations of “brute force” attacks that apply excessive load to your webserver. This type of “brute force” situation can be caused by a massive spike in user activity (i.e., a new advertising campaign). This is a great test to find the traffic threshold for your webserver.
• Ramp Tests—this test uses escalating numbers of users over a given time frame to determine the maximum number of users the webserver can accommodate before producing error messages.
• Various other tests—working with Webserver Stress Tool simply gives you more insight about your website, e.g. to determine that web pages can be requested simultaneously without problems like database deadlocks, semaphores, etc.

Reported readings

Webserver Stress Tool provides a number of robust and flexible reports and logging features to help you gather valuable data about your webserver and website performance. Reports include:

• Click Time—the time it took for a user to complete a pageview (i.e., loading a page and all associated images/objects). This is the time between clicking a link and end of the http last request – which would be the moment a user would see the complete page.
• Time for DNS—the time it takes for a client to resolve a URL's domain name using the client system's current DNS server.
• Time to connect—time to set up a connection to the server.
• Time to first byte (TFB)—time between initiating a request and receiving the first byte of data from the server.
• Request Time (TLB, Time to last Byte)—time for a single HTTP request (i.e. HTML page, image, frameset, etc.).
  Server Bandwidth—the bandwidth achieved by the webserver.
• User Bandwidth—the average bandwidth that was available for each user.
• Sent Requests—the number of requests sent to the server during a period.
• Received Requests—the number of answers received from the server during a period.
• Open Requests—the number of open requests for a given moment.
• Error rates—the number of failed requests per time period, per user, or per URL

Reporting and Logging

This stress and load test tool provides graphs and data in a number of different formats including:

• Several easy to use graphs (visit the sample tests page for sample graphs)
• Summary Text Log
• Detailed Text Log
• User Text Log (one for each user)
• Machine readable CSV files for the request log and the raw graph data

Other Features

Webserver Stress Tool also offers a number of other robust, flexible features to provide you the most comprehensive webserver stress and load test tool on the market. These features include:

• Built-in report generator—reports can be generated as HTML files and MS WORD documents
• Includes a URL recorder (complete web browser) to select the URL(s) you want to test
• Works on any HTTP or HTTP(s) URL
• Can test any script—CGI, ASP, PHP, etc.
• Can also be used to test requests of larger download files (e.g. ZIP)
• Works with any webserver (no part of the software has to be installed on the server)
• Includes support for
  • proxies (not for HTTPS) with optional proxy authentication
  • basic user authentication (username/password)
  • user agent string
  • any HTTP request header lines
  • individual cookie handling for each simulated user (e.g. ASP-Session-IDs)
  • redirected requests and " http-meta-refresh " redirections
  • several IPs for the client machine (up to 5000 IPs)
  • data rate throttling (e.g. to simulate users accessing the server via a slow modem line)
  • timeouts (e.g. to simulate surfers that click away after 20 seconds without answer of the server)
• When testing more than one URL several URL selection methods can be selected to simulate different user behavior
• Tests can run
  • until a specified number of clicks is reached for each user
  • until a specified time has passed
• Tests can be started at a specified time
• Optional link checker can check all URLs for validity
• Optionally all received HTML pages can be written to files
• Optionally all resulting files can be archived in a ZIP file for each test for later reference

What are the benefits of using this tool?
The simplicity of Webserver Stress Tool means any webmaster, programmer, or administrator of a web site can test a webserver/web application under heavy load in real-time. This provides unparalleled ability to quickly adjust webserver configurations for optimal performance (i.e. when a new feature or content is launched).

How long does it take to learn the usage?
Any webmaster or network administrator can use this web testing tool with little guidance. If you want to see how simple it is to assess your webserver using Webserver Stress Tool please have a look at the manual.

How long does it take to install and be running?
After running the standard installer it takes a few minutes to configure and start a test. Several customers reported to us that they found a long searched bug in their software within 15 minutes after ordering and installing Webserver Stress Tool.

What documentation is provided?
Paessler provides a detailed, printable Adobe Acrobat help manual that is both included in the software and downloadable from this website. Webserver Stress Tool also features the same support content integrated into a helpfile.

What is the license model for Webserver Stress Tool?
Please see at the bottom of the order page.

What influence do tool users have on future development of the tool?
We always try to implement suggestions and feature requests from our end users. It is this invaluable input that will continue to make Webserver Stress Test a leading, cost-effective tool for businesses to maximize webserver technologies. Paessler also provides other custom programming upon request.

Recommended Hardware and Operating Systems

The preferred operating environment is Windows XP/2000/2003/Vista on a workstation with at least a 1 GHz processor, 512 MB RAM, and a fast network connection.
The target webservers can be of any operating system.

Test Client Details

Operating System: Although Webserver Stress Tool runs on all 32bit Windows versions (Win95, 98, ME, XP, 2000, NT, 2003) it is strongly recommended to run it on a Windows NT machine or better (i.e. Windows XP, 2000, NT, 2003, Vista) because of limitations in Win9x/ME's IP stack.


Hardware: Serious testing can be conducted with a machine of 1 Ghz and more. More CPU power and multithreading or multiprocessing will be helpful for high traffic scenarios (e.g. when several thousand users are simulated). Try to supply 512 MB of RAM, 1 GB should be enough even for high traffic scenarios. Webserver Stress Tool records the CPU load of the client machine during the test, so you can check after a test whether you need more processing power.


Network: For load tests the network connection between the test client and the server is critical. For the connection between the server and the test client you must provide the full total bandwidth that an equal number of real users would use when accessing your server!

Target Webserver Details

Webserver Stress Tool can test all HTTP servers that are accessible via TCP/IP since nothing has to be installed on the webserver and the connections to the server are using standard HTTP protocol. For example you can use it with the following webserver environments:

• Windows IIS
• Apache on Windows or Linux
• HP/UX
• IBM AIX
• Various flavors of Linux

Brochure

• Web strees tool brochure

Guide

• Web stress test manual