Red Hat Enterprise Linux troubleshooting guide
Subtitle: identify, capture, and resolve common issues faced by Red Hat Enterprise Linux administrators using best practices and advanced troubleshooting techniques
By: Benjamin Cane
Series: Professional expertise distilled; Professional expertise distilled
Publisher: Packt Publishing
Published: 2015
Place of publication: Birmingham, UK
Language: eng
ISBN-13: 9781785287879; 9781785283550
Subjects: Operating systems (Computers); COMPUTERS; Operating Systems; Linux; UNIX; System Administration; Linux & UNIX Administration; Inc Red Hat
Notes: Includes index.
Table of contents: title: Cover; Copyright; Credits; About the Author; About the Reviewers; www.PacktPub.com; Table of Contents; Preface; Chapter 1: Troubleshooting Best Practices; Styles of troubleshooting; The Data Collector; The Educated Guesser; The Adaptor; Choosing the appropriate style; Troubleshooting steps; Understanding the problem statement; Asking questions; Attempting to duplicate the issue; Running investigatory commands; Establishing a hypothesis; Putting together patterns; Is this something that I've encountered before?; Trial and error; Start by creating a backup; Getting help; Books; title: Team Wikis or RunbooksGoogle; Man pages; Red Hat kernel docs; People; Documentation; Root cause analysis; The anatomy of a good RCA; The problem as it was reported; The actual root cause of the problem; A timeline of events and actions taken; Any key data points to validate the root cause; A plan of action to prevent the incident from reoccurring; Establishing a root cause; Sometimes you must sacrifice a root cause analysis; Understanding your environment; Summary; Chapter 2: Troubleshooting Commands and Sources of Useful Information; Finding useful information; Log files; title: The default locationCommon log files; Finding logs that are not in the default location; Configuration files; Default system configuration directory; Finding configuration files; The proc filesystem; Troubleshooting commands; Command-line basics; Command flags; The piping command output; Gathering general information; w; title: show who is logged on and what they are doing; rpm; title: RPM package manager; df; title: report file system space usage; free; title: display memory utilization; ps; title: report a snapshot of current running processes; Networking; ip; title: show and manipulate network settings; title: Netstat; title: network statisticsPerformance; iotop; title: a simple top-like I/O monitor; iostat; title: report I/O and CPU statistics; vmstat; title: report virtual memory statistics; sar; title: collect, report, or save system activity information; Summary; Chapter 3: Troubleshooting a Web Application; A small back story; The reported issue; Data gathering; Asking questions; Duplicating the issue; Understanding the environment; Where is this blog hosted?; Ok, it's within our environment; now what?; What services are installed and running?; Looking for error messages; Apache logs; Verifying the database; title: Verifying the WordPress databaseEstablishing a hypothesis; Resolving the issue; Understanding database data files; Finding the MariaDB data folder; Resolving data file issues; Validating; Final validation; Summary; Chapter 4: Troubleshooting Performance Issues; Performance issues; It's slow; Performance; Application; CPU; Top; title: a single command to look at everything; Determining the number of CPUs available; ps; title: Drill down deeper on individual processes with ps; Putting it all together; A quick look with top; Memory; free; title: Looking at free and used memory; Checking for oomkill; title: Ps; title: Checking individual processes memory utilization