Book Image

Troubleshooting NetScaler

By : Raghu Varma Tirumalaraju
Book Image

Troubleshooting NetScaler

By: Raghu Varma Tirumalaraju

Overview of this book

NetScaler is a high performance Application Delivery Controller (ADC). Making the most of it requires knowledge that straddles the application and networking worlds. As an ADC owner you will also likely be the first person to be solicited when your business applications fail. You will need to be quick in identifying if the problem is with the application, the server, the network, or NetScaler itself. This book provides you with the vital troubleshooting knowledge needed to act fast when issues happen. It gives you a thorough understanding of the NetScaler layout, how it integrates with the network, and what issues to expect when working with the traffic management, authentication, NetScaler Gateway and application firewall features. We will also look at what information to seek out in the logs, how to use tracing, and explore utilities that exist on NetScaler to help you find the root cause of your issues.
Table of Contents (17 chapters)
Troubleshooting NetScaler
Credits
Notice
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Disk issues


There are two kinds of disk issues that NetScaler administrators may come across:

  • Disk hardware issues: There are three ways to identify disk hardware issues:

    • SNMP Alerts is one way to identify it. You can configure the alarm HARD-DISK-DRIVE-ERRORS

    • Look for entries in the /var/log/messages file – the keyword is TIMEOUT

    • Run the hardware analysis file /netscaler/ns_hw_err.bash, which will run through all the log files and capture the TIMEOUT entries for you.

    Note

    Note that a very occasional TIMEOUT can occur with a perfectly healthy NetScaler. There is, however, a problem if you see a few of them in succession and that is the symptom you are looking for. RMAs can involve either simply replacing the SSD, which is less disruptive, or sometimes replacing the unit, if it's the controller which is failing (which is a lot rarer).

  • Disk space issues: NetScaler relies on the hard disk not just for storing logs and traces, but also as swap space to improve performance. Consequently, when the...