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Problem Analysis andTroubleshooting

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Module Overview

Types of problems that affect IIS

How to identify them

What can cause them

How to troubleshoot themLots of hands on!

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Section 1: Common IIS-Related Problems

Application Crash

100% CPU Hang

0% CPU Hang

Performance IssuesMemory Leaks

Startup Problems

Access Issues

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Application Crash - How to Identify

Browser errors The connection with the server was reset

The remote procedure call failed

The RPC server is unavailable

ASP 0115 / HTTP 500

Event logs

IIS logs

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Application Crash - Possible Causes

Stack overflow

Stack corruption

Heap corruption

Divide by ZeroNull pointer dereference

Any other unhandled exception

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Application Crash - How to Troubleshoot

Review event logs

Review IIS logs for HTTP 500/ASP 0115 errors

Switch off all proactive recycling

Run ADPlus or DebugDiag in crash modeAnalyze memory dump in WinDBG

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100% CPU Hang - How to Identify

Browser shows only blank page or times out

Pages take a long time to load on browser

Check CPU usage in Task Manager or PerformanceMonitor

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100% CPU Hang - Possible Causes

Long loops

Infinite loops

Memory leaks

String manipulationGarbage collection

Insufficient hardware

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100% CPU Hang - How to Troubleshoot

Switch off all proactive recycling

Wait for problem to occur again

Gather Perfmon data

Run ADPlus or DebugDiag in hang modeAnalyze Perfmon data

Analyze memory dump in WinDBG

Perform live debug to identify the root cause, if required

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0% CPU Hang - How to Identify

Browser shows only blank page or times out

Create simple .htm, .asp, .aspx pages

Attempt to browse to each test page

Does process recover if load is removed?Easy to confuse with performance issues

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0% CPU Hang - Possible Causes

Serialization

Deadlocks

Orphaned critical sections or monitors

Microsoft Visual Basic (VB) RIM/UE issuesFailing COM/database/remoting calls

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0% CPU Hang - How to Troubleshoot

Switch off all proactive recycling

Enable process orphaning

Run DebugDiag or ADPlus in hang mode

Analyze memory dump in WinDBG

!locks

!critsec

!syncblk

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Performance Issues - How to Identify

Users report application is running slowly

Application appears to hang

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Performance Issues - Possible Causes

Too many to mention!

Serialization

Long COM/database/remoting calls

Insufficient hardware

Network congestion

Poor quality application code

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Performance Issues - How to Troubleshoot

Performance Monitor

Perfmon baseline logs

Stress testing tools

Application Center Test

WCAT

Log Parser

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Memory Leaks - How to Identify

Popup message stating "System out of virtual memoryRandom problems associated with a lack of virtualmemory

Degrading system performance and excessive swapping

Failed memory allocations

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Memory Leaks - Possible Causes

Application failing to free private memory or resourceallocations

Includes memory, user and gdi objects, handles, threads,etc.

Abnormal code paths which bypass free logic

Logic errors

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Memory Leaks - How to Troubleshoot

Performance MonitorPMON.EXE

DebugDiag (LeakTrack)

UMDH.exe

LeakDiag (Microsoft PSS Tool)

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Startup Problems - How to Identify

IIS fails to startIIS starts very slowly

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Startup Problems - Possible Causes

Large metabase filesPermissions

Corrupt/missing Machine Keys

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Access Issues - How to Identify

Users receive unexpected authentication promptsUsers get Access Denied messages

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Access Issues - Possible Causes

Incorrect authentication schemes configuredDC comms issues

Incorrect user or process identity permissions

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Access Issues - How to Troubleshoot

Network Monitor (NetMon)WFetch

AuthDiag

Log Parser

ASPNET_regiis

Permissions Verifier

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Section 2: Labs - Troubleshooting Scenarios

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Action Planning Exercise

Think about how youll apply the concepts and/or

practices youve learned when you return to your

workplace.

1.Summarize your action items

2.Questions for your trainer?3.Class discussion