dmo.ca/ tag/ linux

I have a new disk that uses 4kb sectors. Unfortunately, on the system it's installed in, none of the partitioning tools deal with this automatically, leading to near-guaranteed misalignment and slower performance, or so says the Googled results (JFGI yourself... I'm too lazy to paste the links here). So, here's what I did:

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Posted Fri 28 Oct 2011 02:53:58 AM UTC Tags: linux

A while back, I posted about detecting virtualization on Linux from a shell, using various tricks. Around that time, I also implemented those tricks as a perl script for internal use at work with the intent of eventually cleaning it up for public consumption. I finally got around to doing it, and the result is Sys::Detect::Virtualization availabe from CPAN, or from GitHub.

Currently, it can only handle Linux, and is only tested on a small number of virtualization hosts. Patches are welcome.

Posted Thu 25 Feb 2010 06:38:00 PM UTC Tags: linux

I recently moved our automated testing systems from a KVM+Qemu setup to Linux-VServer. We didn't need the overhead of a full virtual environment, even one as lightweight as KVM. However, there was a little snag -- 127.0.0.1 didn't work correctly.

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Posted Tue 14 Jul 2009 04:20:10 PM UTC Tags: linux

etckeeper is a tool, packaged in Debian, that lets you track revisions to /etc in a Git repository. Here's how to install and configure it.

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Posted Sat 16 May 2009 01:45:14 AM UTC Tags: linux

At my job we have need of a high-performance hash lookup database in our antispam product. It's used to store Bayes tokens for quick lookups on individual scanning systems, and is read-only in the fast path (mail scanning) with updates taking place in another process. For the last few years, we've been using a plain old BerkeleyDB hash database via Perl's DB_File, but with all the hype about Tokyo Cabinet and its benchmark results I figured it was time to take a look.

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Posted Sat 16 May 2009 01:45:14 AM UTC Tags: linux

A while ago, I blogged the chrooting of bind9 on Debian, so I wouldn't forget how to do it. Things have changed slightly for Lenny, so here's the update.

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Posted Sat 16 May 2009 01:45:14 AM UTC Tags: linux

At work we use git, and have an extensive suite of tests for our code, and a set of scripts we use to kick them off manually. Unfortunately, we don't have a nice way to run them automatically.

Here's what I want, described here so I don't forget it. Tomorrow, I'll start looking for something that meets these needs, or can be hacked to do so. Maybe I'll have to implement it all, maybe not.

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Posted Sat 16 May 2009 01:45:14 AM UTC Tags: linux

Every now and then, I move my nameserver to a new machine, and I have to google for the recipe for chrooting it on Debian. So, this time, I'm documenting it here.

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Posted Sat 16 May 2009 01:45:14 AM UTC Tags: linux

Update: You may be interested in the perl module implementing these tricks.

Frequently, our customers want to install our software in a virtual machine. This can be OK, but frequently they hit a CPU, memory, or IO limit caused by running in a constrained virtual environment. When this happens, we really like to know if they're running under virtualization when we try to support them. Here's some tricks to detect, from a shell, if the system is virtualized.

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Posted Sat 16 May 2009 01:45:14 AM UTC Tags: linux