Ferry Boender
Programmer, DevOpper, Open Source enthusiast.
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Category: sysadmin
VirtualBox: List guest IPs
I often clone VirtualBox machines as a quick way to get a fresh box to test some stuff on. The problem is, I don’t know which IP the new clone gets assigned. Fortunately, if you’ve got VirtualBox Guest Additions installed on the guest, you can use the guestproperty to get the IP. Here’s a quick […]
Tmux scrolling with shift-pageup/down
Put this in your .tmux.conf to enable scrolling using the Shift-PageUp/Down keys: set -g terminal-overrides ‘xterm*:smcup@:rmcup@’
Multiple VirtualBox VMs using one base image (copy-on-write)
As a developer and systems administrator, I use VirtualBox a lot for building binaries, testing upgrades, etc. It always struck me as a waste that I’d have to clone an entire HD image whenever I needed a fresh install of a machine. Why couldn’t I just use a single base image for each Virtual Machine, […]
Stop Pingback/Trackback Spam on WordPress
I guess the spammers finally found my blog, cause I’ve been getting a lot of pignback/trackback spam. I tried some anti-spam plugins, but none really worked, so I disabled pingbacks altogether. Here’s how: First, log into wordpress as an admin. Go to Settings → Discussion, and uncheck the Allow link notifications from other blogs (pingbacks […]
Creating simple Debian packages
Here’s a quick way to create your own Debian package. This is merely a simple package which will not be included in the official Debian repositories, so we can ignore most of the Debian packaging guidelines. First off, we need to create a directory which shall hold the contents of the package. In this case, […]
Netfilter (iptables) performance tests
Here’s a nice study on the performance of Linux’s network firewalling/packet mangling layer: Netfilter Performance Testing Conclusions (mine, based on the study): Netfilter/iptables is up to par with other filter solutions when it comes to plain routing. Netfilter/iptables is not up to par with other filter solutions when it comes to connection tracking (basically just […]
Minecraft Server optimization
The Minecraft server was running very slowly and gobbling up a significant amount of memory. Game-play was laggy, chunk loading stuttery and I saw a LOT of the following message in the server.log: [WARNING] Can’t keep up! Did the system time change, or is the server overloaded? I decided to unleash my google-fu, dug through […]
Filesystem Latency
There’s an interesting on-going series of articles on file system latency over at Brendan’s Blog. Usually when system administrators look into I/O performance, we look at the I/O of the disks. This is usually fine for a rough estimate of raw disk performance, but there’s a lot more going on between the actual application and […]
SSH Tips and Tricks
(The lastest version of this article is always available in stand-alone HTML format and in PDF format. The original AsciiDoc source is also available. Please link to the HTML version, not this Blog post!) SSH is capable of more than you’d think! This article describes some of the lesser known features and configuration options. It […]
Easy way to create a Debian package and repository
Interesting article over at Linuxconfig.org: This article describes a simple way on how to create a home made debian package and include it into a local package repository. Although we could use a existing Debian/Ubuntu package, we will start from scratch by creating our own minimalistic unofficial debian package. Once our package is ready, we […]
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