Notes

Notes / Overview

Documentation on this site

The documents on this site comprise information compiled over the last 25 years or so by many many Admins. Alot of this follows conventions of the companies we've worked for, and may or may not be the way you would do it, or the way you would want to do it. We will attempt to explain why and where you would want or wouldn't want to utilize some of these conventions.

Linux Distros

Initially these docs are based on what we've seen/used in enterprise environments at the companies we've worked for. So far, this has been RedHat Linux and RedHat Linux compatibles (CentOS Linux / Scientific Linux / OracleLinux / Whitebox Linux). While we have seen on job reqs, and understand there is also a demand for Admins who also use Suse or Ubuntu in Enterprise env's, we've not actually seen this in the Enterprise for the hundreds of companies we've worked for. That being said, we wish that The Linux Source would be Distro agnostic, and would appreciate any help adding docs/details for some of these other major Distros as well.

The term Enterprise mentioned in the docs is a general term for RHEL (RedHat Enterprise Linux) and compatibles (CentOS / OracleLinux / etc.). This is just a generic way to refer to a release without mentioning a specific Distro, since RHEL / CentOS / OracleLinux / etc. Release 5 aka Enterprise 5 is basically identical and where Enterprise 5 is mentioned, that command can be used on all of the RedHat compatible Distros. Fedora is slightly different, as the versioning is not in sync with these other distros. If using Fedora, it would be best to determine the applicable version the doc refers to by checking wikipedia release history to see which Fedora version coincides with which Enterprise version.

Conventions

Many examples show commands typed at a prompt. The convention is something like;

# commandtodosomething

This is not a comment, please don't include the # if copying/pasting from one of these documents. Also, note that the normal prompt as a non-priveledged user is $ and the normal prompt when root is # however the convention here is to use # for all prompts so please ignore the fact that the # prompt in the documents are also shown for a non-root user AND/OR don't assume that since the prompt is # that it means the command is typed in as root.

All data on /home

Most of the documentation follows various companies convention of separating their code and processes from the OS by dumping everything on/under /home and keeping data/logs/etc. there. This is fine if that is the convention you wish to follow, however, this is difficult to deal with if you are running a secure env using SELinux. There are some advantages with keeping everything on /home, primarily it is easy to reinstall the OS and reformat/rebuild all OS partitions without touching /home and keeping all your code/data/logs/etc. intact. One other primary reason to keep OS and application separate by using /home, when application logs fill up /tmp or /var, you don't crash the OS when it no longer has space left for temp files, or losing OS logs when there's no space left to record issues the OS is having when things go awry with the application.

Whether you choose to keep app and OS separate and run your non-OS specifics from /home is up to you, if you don't (or if you are running SELinux), please ignore and DO NOT do the steps for moving items to home. For example, and using mySQL as a case in point, ignore the commands to move it off of /var;

mv /var/lib/mysql /home/ ; ln -s /home/mysql /var/lib/