Check your ext3 filesystems for unexpected fscks on reboot

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Nov 8, 2012
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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

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Jul 14, 2011
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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

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Jun 30, 2011
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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 […]

In Linux, Unix

Linux and free memory

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Feb 21, 2011
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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 […]