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Quick Setup of Salt on CentOS/RHEL

August 21, 2014 – 2:58 pm |

Just some quick notes on installing and configuring Salt master server and minions to run remote commands for various sysamdin needs.

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Networking

Unix and Linux network configuration. Multiple network interfaces. Bridged NICs. High-availability network configurations.

Applications

Reviews of latest Unix and Linux software. Helpful tips for application support admins. Automating application support.

Data

Disk partitioning, filesystems, directories, and files. Volume management, logical volumes, HA filesystems. Backups and disaster recovery.

Monitoring

Distributed server monitoring. Server performance and capacity planning. Monitoring applications, network status and user activity.

Commands & Shells

Cool Unix shell commands and options. Command-line tools and application. Things every Unix sysadmin needs to know.

Apache »

Installing GoAccess on CentOS/RHEL

June 24, 2014 – 11:02 am |

GoAccess is a simple but useful “top”-like CLI utility giving you a quick overview of the Apache access_log entries. Read the full story »

NTP Client Configuration on CentOS

May 15, 2014 – 8:31 pm |

Just some quick note on configuring NTP client on CentOS/RHEL/Fedora and forcing time update. Just got tired of having to remember these steps every time I run into NTP.

Searching Log Files

April 18, 2014 – 4:40 pm |

This is a quick example of finding the first and last occurrence of an event in the log file. This can be useful for determining the service outage window and for general troubleshooting. In the example below I am looking at the PostFix maillog file, trying to figure out the duration of the problem I’ve been having with one of the mail relay servers.

WordPress Remove Extra Line Breaks

December 2, 2013 – 3:09 pm |

Frequently, imported posts or posts created by auto-blogging plugins will create unnecessary tabs, newlines, and line breaks. This has a negative impact on readability and aesthetics of your site. If you cannot address the problem …

MySQL mysqlhotcopy Script

December 2, 2013 – 1:30 pm |

Here’s a simple script to automate mysqlhotcopy runs from cron to backup multiple MySQL databases. The script loops through the list of databases and kicks off an instance of mysqlhotcopy in the background for each one. Really, …

Monday Rant: HP’s Web Site Fail

November 18, 2013 – 8:21 pm |

Every time I come across a link leading to HP’s angry garden salad of a Web site, I feel as if I stepped in chewing gum. Unfortunately for me, being a sysadmin means I have …

Dynamic Variables in BASH

October 10, 2013 – 9:32 am |

Assigning variables is easy if you know how many you have and what they are called. The value of a variable can be, well, variable. But the names and number of variables need to be …

Free Rescue CDs for Windows

October 5, 2013 – 11:32 am |

This is just a quick summary of the more popular rescue CDs out there. All of these are Unix-based bootable ISOs. Some are available as self-burning EXE files, which may be useful if you don’t …

Linux Man Pages (man1)

October 1, 2013 – 3:03 pm |

The current version of manual pages for the most common Linux commands and options. Just for your online convenience.

My Script Won’t Run from Cron!

September 27, 2013 – 10:36 am |

This is a fairly common issue with running scripts from root cron: the script works perfectly when ran manually from command line, but fails in unexpected ways when running automatically from root cron.

Configure Anonymous FTP on Solaris 10

August 25, 2013 – 2:30 pm |

Below are basic steps for configuring anonymous FTP service on Solaris 10. Use with caution.

Enable Basic FTP Server on Solaris 10

August 22, 2013 – 2:22 pm |

Here are a few simple steps to enable a basic FTP server on Solaris 10.

Simple Network Discovery

August 21, 2013 – 11:38 am |

The bash script below will scan the specified IP range and use dig and nmap to try to determine the fully-qualified domain name, type and the operating environment of any device that responds to network …

Basic Samba Configuration on Solaris 10

August 20, 2013 – 2:21 pm |

Here’s a sample process for installing and configuring a basic Samba server on Solaris 10.

Solaris 10 NFS Server Configuration

August 16, 2013 – 2:01 pm |

As far as NFS servers go, I think the best platform in terms of performance and stability is Solaris running on SPARC architecture. Perhaps this has something to do with the fact that NFS was created for Solaris. Over the years I’ve been working with NFS servers on AIX, HP-UX, Linux, BSD, etc. It always worked better on Solaris.

RPC: Authentication When Mounting Solaris NFS Share

August 16, 2013 – 1:37 pm |

When mounting an NFS share from a Solaris 10 server, you may encounter the “RPC: Authentication” error. You may notice that you are able to mount the share via NFSv4, not not NFSv3. On the NFS server the /var/adm/messages may show the following errors for the client…

Friday Rants

June 21, 2013 – 7:16 pm |

I always had a hard time explaining to non-tekkies what I do for living. Well, today I heard the best ever description of my job. You know the guy who walks behind a circus elephant with a large bag? In my case the elephants are made by HP, IBM, and EMC.

Install Pflogsumm PostFix Log Summarizer

March 12, 2013 – 9:58 am |

Pflogsumm is yet another log analyzer/summarizer for Postfix. It is written in Perl and has been around for a while. Very simple to install, so I writing this post mostly as a note to myself. …

Installing Sendmail Analyzer on RHEL/CentOS

March 11, 2013 – 11:35 pm | One Comment

The Sendmail Analyzer can be useful for visualizing your Sendmail/Postfix log. The commands below can be copy-pasted as root on default installations of RHEL and CentOS 5/6 with default Postfix and httpd. If your configuration …

Fast IP Range Scanner in Bash

February 22, 2013 – 2:53 pm | 4 Comments

Just a simple script to scan an IP range and do a reverse DNS lookup. This can be useful for building an inventory of systems on your LAN. Just make sure to give your network …

Filesystem Performance Testing Using dd

February 5, 2013 – 3:35 pm | 5 Comments

Below is a simple script to test filesystem read/write performance using dd with varying blocksize parameter. This can be useful for testing local filesystems as well as network-mounted filesystems. The end result will be a …

Uninstall PostgreSQL from Ubuntu

January 4, 2013 – 1:22 pm | 2 Comments

Ok, so this is a very simple one: uninstall PostgreSQL running on Ubuntu. There are a bunch of pieces to the database server and just running “apt-get remove postgresql” will still leave you with with a bunch of leftovers

A Faster Way to Delete Many Folders

October 24, 2012 – 11:00 pm | 4 Comments
A Faster Way to Delete Many Folders

This issue is particularly annoying when dealing with expansive directory structures mounted via NFS. Let’s say you have a directory with ten thousand folders and each of them has more subfolders and files. And you …