Book Image

Red Hat Enterprise Linux Troubleshooting Guide

By : Benjamin Cane
Book Image

Red Hat Enterprise Linux Troubleshooting Guide

By: Benjamin Cane

Overview of this book

Red Hat Enterprise Linux is an operating system that allows you to modernize your infrastructure, boost efficiency through virtualization, and finally prepare your data center for an open, hybrid cloud IT architecture. It provides the stability to take on today's challenges and the flexibility to adapt to tomorrow's demands. In this book, you begin with simple troubleshooting best practices and get an overview of the Linux commands used for troubleshooting. The book will cover the troubleshooting methods for web applications and services such as Apache and MySQL. Then, you will learn to identify system performance bottlenecks and troubleshoot network issues; all while learning about vital troubleshooting steps such as understanding the problem statement, establishing a hypothesis, and understanding trial, error, and documentation. Next, the book will show you how to capture and analyze network traffic, use advanced system troubleshooting tools such as strace, tcpdump & dmesg, and discover common issues with system defaults. Finally, the book will take you through a detailed root cause analysis of an unexpected reboot where you will learn to recover a downed system.
Table of Contents (19 chapters)
Red Hat Enterprise Linux Troubleshooting Guide
About the Author
About the Reviewers

Recovering the filesystem

Now that we know why the filesystem is in the Read-Only mode, we can resolve it. Forcing the filesystem to go from Read-Only to Read-Write is actually pretty easy. However, because we don't know all of the circumstances around the failure that caused the filesystem to go into the Read-Only mode, we must be careful.

Recovering from filesystem errors can be extremely tricky; if not done properly, we could easily find ourselves in a situation where we have corrupted the filesystem or in other ways caused partial or even full data loss.

Since we have multiple filesystems in the Read-Only mode, we will first start with the /boot filesystem. The reason we are starting with the /boot filesystem is because this is technically the best filesystem to experience data loss. Since the /boot filesystem is only used during the server boot process, we can simply ensure that we do not reboot this server before the /boot filesystem can be recovered.

Whenever possible, it is always best...