Web Stress Testing

1
Web Stress Testing

• Matt Odhner
• Program Manager
• Application Center
• Microsoft

2
Topics to be Covered

• Important web hosting statistics
• What stress testing solves common stress
  testing issues
• Web Application Stress tool demonstration
• Understanding the report data
• What a commercial stress tool needs
• Application Center Test (ACT) demonstration
• Visual Studio integration
• The importance of bandwidth testing
• Other ACT features
• Capacity planning

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Web Hosting Statistics

• Popular web sites receive over 40,000,000
  requests per day
• Web hosting is expected to be a 14.6 billion
  industry by 2003
• Newport Group study revealed 52 of web
  applications failed to scale, 60 had no
  performance testing, only 25 used a testing tool
• Zona Research found that 4 billion a year is
  lost due to slow and failed web pages

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Stress Testing Solves

• Stability issues - unexpected downtime and poorly
  written COM objects
• Performance problems locate bottlenecks and
  whether the application will handle peak loads
• Capacity planning - how many machines are needed
  to support usage
• Plus, it avoids financial losses and ensures
  customer satisfaction

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Stress Testing Locates Bottlenecks

• Memory
• Processor
• Network
• Hard disk
• COM component

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Common Stress Test Issues

• Invalid test platform
• Invalid script
• Thread safety issues with unstable server COM
  components
• Active Server Page script errors and GLOBAL.ASA
  issues
• Insufficient processor power and/or scripts are
  too complex for the hardware

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Traditional Test Bed
Web server
Member Stress Client
Member Stress Client
Controller Stress Client
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Approaches to Stress Testing

• Confirm that the application functions under load
• Find the maximum requests per second my
  application can handle
• Determine the maximum number of concurrent
  connections my application can handle
• Test the application with x number of unique users

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Creating the Script
Scripts view - create, edit, delete, and run
stress scripts.
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Creating the Script (contd)

• Record using your browser this method is
  recommended because all page elements are
  captured.

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Script Configuration - Settings
Concurrent browser connections
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Script configuration - Users

• Users view - manage user names and passwords.

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Script Configuration - Clients
Clients view - add and remove the client machines
used to stress the web server(s)
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Script Configuration - Script Item Details
Script item details modify query string, edit
POST data, use SSL, query RDS.
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Performance Monitor Data

• Collect performance monitor
• counters from within the tool

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Scriptable Object Model
Sub AddNewScript() Set objWAS
CreateObject("WAS.EngControl.1") Set
objScripts objWAS.Scripts Set objScript
objScripts.Add objScript.sName "A New
Script" objScript.ScriptItems.sServer
"www.targetserver.com" MsgBox "The new
ScriptID is " objScript.ScriptID End Sub
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Session Trace Option
h Selected new user User2, password,
ASPSESSIONIDGQQGQNYGMPBBLMOAFBPBPDFAJLMCCFCO
Account6001 h closed socket h linger is
on, linger timeout is 0 h connected to the
server. 172.30.170.21780 h sending request
to server (470 bytes) GET /fmstocks/_NewAccount.as
p HTTP/1.1 Host localhost
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ASP Client
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Reports Tabular Report Data

• Reports view - analyze the results of a test.

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Time to First and Last Byte
0 ms
Request
9 ms
6 ms
Response
Time To Last Byte
Time To First Byte
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Calculating ASP Performance

• MHz Cost N S avg (Pt) / avg(Rps)
• Where
• N Number of Processors
• S Speed of Processors
• Pt System Total Processor Time
• Rps ASP Requests per secondReports view -
  analyze the results of a test.

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Calculating ASP Performance

• Example a test using a 2 processor web server
  achieved 350 requests per second, with the
  processors 70 utilized.
• So, this works out to
• 2 processors 400 MHz gt 800 MHz
• 70 processor utilization gt (800) (0.70)
• gt 560 MHz used
• 350 ASP requests per second 560/350
• gt 1.6 million cycles per ASP request

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More About Web Application Stress Tool

• Designed to meet internal test needs
• http//webtool.rte.microsoft.com contains
• Searchable knowledge base
• Tutorial of main features
• Latest download
• Object model sample scripts
• Peer support on the discussion alias
  webtool_at_microsoft.com
• Online help contains samples
• The tool respects ROBOTS.TXT

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What is Needed in aCommercial Stress Test Tool?

• All of the features in Web application Stress,
  Plus
• Accurate simulation of client connection
• speeds
• Running a script a specific number of iterations
• Testing of servers in multiple domains
• Handle complex applications that require
• conditional responses
• Capable of changing subsequent requests based on
  the response of a previous request
• Functional and performance testing
• In-depth reporting and troubleshooting

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MicrosoftApplication Center Test
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Significant Features

• Integration with Visual Studio
• IP router technology
• Data collector to replay actual web site traffic
• Completely scriptable, even as the test is
  running
• Graphical and tabular reporting
• Capacity planning
• Can import Web Application Stress scripts

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1. Visual Studio Integration
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Visual Studio Integration (contd)
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Bandwidth Statistics

• 58 of web site users said download speed was a
  primary factor that influences them to return
  to a site (Forrester Research)
• Web surfers give a site about 10 to 15 seconds
  to display before they hit the stop button and
  go to a different site
• Bandwidth is not expected to improve soon
• Chart shows forecast for the year 2003

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2. IP Router Technology
Web farm
T1
T3
56 K
28.8
Client computers
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IP Router Technology (cont'd)
Web cluster
ACT
Local Area Network
Delay prior to sending each packet so that1,588
bits per second is maintained
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IP Router Technology (cont'd)
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3. Data Collector
Internet traffic
Replays exact traffic
Client computers
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4. Completely Scriptable
If IsObject(Session) False Then Set Session
CreateObject("ACT.Session") End If Set oRequest
Session.CreateRequest oRequest.Path
"/samples/cookie.asp" oRequest.Headers.Add
"Connection", "Close" oRequest.Headers.Add
"Cookie", "FirstNameMattLastnameOdhner" Set
oConnection Session.CreateConnection("MATTOD15")
Set fs CreateObject("Scripting.FileSystemObject
") Set writeToFile fs.OpenTextFile("c\test.txt"
, 8, TRUE) thePath oRequest.Verb " "
oRequest.Path " " _ oConnection.Send(oRequest
).ResultCode chr(13) chr(10) writeToFile.Writ
e thePath writeToFile.Close
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Reporting - Tabular Reports
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Reporting - Connections vs. TTFB TTLB
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Reporting - Comparing Scripts
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6. Capacity Planning
1. Manual capacity planning
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Capacity Planning (cont'd)
2. Historical capacity planning
Internet
Filter
Filter
Filter
Web cluster
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Capacity Planning (cont'd)
3. Calibrated capacity planning
Web farm
Client computers
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Summary

• Web Stress tools give answers to the problems of
  Web application stress, via
• Modeling
• Prediction
• Identification of bottlenecked resources
• Provision of performance Metrics to help
• developers decide what content to deploy
• So - employ one today to improve your web
  application's performance!

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Resources - Further Reading
http//www.microsoft.com/TechNet/iis/sol.asp htt
p//msdn.microsoft.com/library/techart/windnami
stakes.htm http//msdn.microsoft.com/workshop/ser
ver/asp/server102599.asp http//msdn.microsoft.co
m/workshop/server/asp/server092799.asp http//msd
n.microsoft.com/workshop/server/asp/server122799.a
sp http//www.microsoft.com/siteserver/commerce/s
upport/highcapacity.htm
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Resources - Other Web Stress Tools Available
Mercury Interactive, Loadrunner/Winrunner -
http//www.merc-int.com/products/ Radview,
Webload - http//www.radview.com/webload/ RSW,
eLoad - http//www.rswsoftware.com/ Segue,
Silkperformer - http//www.segue.com/html/s_soluti
ons/silk/s_performer.htm Bluecurve, Dynameasure
- http//www.bluecurve.com/products/products.htm
Rational, Rational Suite / PerformanceStudio -
http//www.rational.com/products/rs/pstudio/index.
jtmpl
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Questions?

• Matt Odhner
• Program Manager
• Application Center
• Microsoft