Check your ext3 filesystems for unexpected fscks on reboot

By
Nov 8, 2012
No Comments

One “feature” of Linux systems is that ext2/ext3 filesystems can be automatically (and unexpectedly) fsck’d upon reboot. Technically, it’s done at mount time, after a configurable number of mounts or days. In theory, I suppose it makes sense to periodically check flaky filesystems running on low-end hardware. In practice, however, it frequently comes as a […]

Setting up a CentOS repository

By
Jul 14, 2011
5 Comments

To celebrate the release (finally!) of CentOS 6, here’s how to create a local repository and keep it up-to-date. The first step is to create the directory structure for the repository.  You’ll need about 30GB of free space in the filesystem you use.  Let’s assume we have a mountpoint /repo that we want to use: […]

In Linux

Using dmidecode on Linux to find host information

By
Jun 30, 2011
No Comments

A handy utility that I use frequently to find information on my systems is dmidecode.  We run Dell PowerEdges, and I frequently need to find the Service Tag for licensing, support, and whatnot.  The utility is a way to get information on the system BIOS, firmware versions, etc. With dmidecode, I can get this information […]

Active Directory Authentication in Tomcat 6

By
Feb 23, 2011
No Comments

Note: Here’s a writeup that I did about two years ago, but should still be valid for Tomcat 6. Active Directory Configuration Create an account in Active Directory to be used for enumerating users and groups.  Active Directory does not allow anonymous binds. Tomcat Configuration These instructions assume that you are modifying a clean install […]

In Linux, Unix

Linux and free memory

By
Feb 21, 2011
No Comments

How much memory really is free on a Linux system, anyway? This is something that I have seen cause confusion in the past. A DBA, developer, or consultant is trying to figure out why a particular application or program is running poorly (it’s never, ever their Java or SQL code), runs top or free, sees […]