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Web Server Administration
Chapter 11
Monitoring and Analyzing the Web
Environment
Overview
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Monitor operating systems
Monitor Web servers
Monitor other Web applications
Learn about some analysis tools for
Web servers
Monitoring Operating Systems
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Typically you analyze log files
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Logs are used to detect problems
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They contain information regarding certain
events
OS, application, or security problems
Various tools can monitor performance
Should create baseline at beginning of
OS lifecycle for comparison purposes
Monitoring Windows
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Performance monitoring allows you to
compare system performance over time
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You can set multiple counters and watch
them in real-time
Windows Task Manager highlights CPU
and memory usage
You can modify services to notify you if
a service fails
Windows Event Viewer
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The event viewer contains six event types shown in the left pane
Windows Event Logs
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System and application events display three
levels of messages
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Information
Warning
Error
Because many messages can be generated, a
filter focuses on what you want to see
Over time, the logs fill up so you should clear
them or save them
Monitoring Linux
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Logging is controlled by the syslogd daemon
Facilities represent daemons that used syslogd
Most facilities are listed below
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Apache uses local7
Eight Levels of Message
Priorities in syslogd
Monitoring IIS
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IIS has specific counters for use in the
Performance Monitor
The System event viewer provides specific
information
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If IIS did not start, you can find out why
IIS has extensive logging capabilities
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Default log format used by various third-party
applications that analyze logs
You can create custom logs
Sample IIS Log
Monitoring Apache
Error Logs
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By default, syslogd sends Apache
messages to /var/log/boot.log
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Location of the error log
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ErrorLog logs/error_log
logs refers to /var/log/httpd
You can create a different error log for
each virtual host
Monitoring Apache
Transfer Logs
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Transfer logs tell you about the use of your
Web site
Default log based on combined format
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Determined by the CustomLog directive in
httpd.conf
There are a number of sample formats or you can
create your own
By default, they are stored in
/var/log/httpd/access_log
Monitoring DNS
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BIND uses a logging statement that you
configure in named.conf
Define logging in two parts
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Channel defines where logging is sent
Category defines what will be sent
If the channel is going to a file, use the
versions option to define the number of
backups
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Size option sets maximum size of the file
print-time adds the date and time to the file
BIND Categories
BIND Logging Entry
logging {
channel "techno_channel" {
file "named.log" versions 4 size 10m;
print-time yes;
};
category "resolver" {
"techno_channel";
};
};
Monitoring Exchange 2000
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Uses Application portion of Event viewer
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Should filter out informational messages because
there are over 50 just when it starts
You can enable four types of logs
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audit – access to mailboxes
protocol – commands used for SMTP, etc
message tracking – senders and receivers
diagnostic – analyze detailed problems
Analysis Tools for the Web
Server
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Analysis tools extract system data from logs
and format the data
For IIS, one of the popular tools is
WebTrends from NetIQ
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Helps you determine the source of Web traffic
Determines which pages are most popular
Nearly 50 different reports
123LogAnalyzer is available for both IIS and
Apache
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Many reports are similar to WebTrends
However, you cannot compare reports over time
Summary
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Monitoring operating systems typically
involves performance monitor graphics and
analyzing log files
When monitoring systems, start with a
baseline
In Windows, Event Viewer is the primary
utility
BIND 9 DNS has extensive logging capability
Analysis tools take data in logs and help you
make sense of it in an easy to read format