In the “Mendix Cloud” we are hosting thousands of Mendix Apps. All these Apps are running on top of the Oracle Java Runtime Environment (JRE) in Debian Linux environments. We use java-package to package the Oracle JRE to be able to easily redistribute it to all our servers. After packaging and putting the Debian package in our local apt repository the Oracle JRE can be easily installed via apt-get. # apt-get install oracle-java8-jre When there is an update available of the Oracle JRE, we again package the new version and put it in our local apt repository....

In January 2007 I bought my first OS X device, a white 13.3-inch MacBook, running OS X 10.4 Tiger on a 2.0Ghz Intel Core 2 Duo processor, having 1GB of RAM. Along the way I upgraded it to 2GB RAM and gave it a fantastic boost by replacing the HDD by an Intel 320 Series SSD. I also upgraded OS X to 10.5 Leopard, 10.6 Snow Leopard and in the end to 10....

I recently upgraded my DNS server to Debian Jessie. In fact I reinstalled it from scratch and used puppet to install and configure all the required components. This DNS server, running bind9, is the authoritative nameserver for nethuis.nl. nethuis.nl uses DNSSEC. To apply DNSSEC I used dnssec-tools, which gives you tools like zonesigner, rollerd and donuts to sign, roll and check your DNSSEC enabled zones. Two years ago I had a hard time setting this up, hitting various bugs in dnssec-tools 1....

In October 2012 I started using bcache as an SSD caching solution for my Debian Linux server. I’ve been very happy about it so far. Back then I used a manually compiled 3.2 Linux kernel based on the bcache-3.2 git branch provided by Kent (which has been removed). This patch needed to be applied to make bcache work with grsecurity. I also created a Debian package of the bcache-tools userspace tools to be able to create the bcache setup....

Imagine… Imagine if you could setup a new Mendix hosting environment in seconds, everywhere. A lightweight, secure and isolated environment where you just have to talk to a RESTful API to deploy your MDA (Mendix Deployment Archive) and start your App. Since the 2nd quarter of this year a great piece of software became very popular to help to achieve this goal: Docker. Docker provides a high-level API on top of Linux Containers (LXC), which provides a lightweight virtualization solution that runs processes in isolation....

After 2,5 years and about 100 commits I’ve tagged version 0.4 of Collectd Graph Panel. This version includes a new interface with a sidebar for plugin selection. Javascript library jsrrdgraph has been integrated. Graphs will be rendered in the browser using javascript and HTML5 canvas by setting the “graph_type” configuration option to “canvas”. This saves a lot of CPU power on the server. Jsrrdgraph has some nice features. When rendered, you can move through time by dragging the graph from left to right and zoom in and out by scrolling on the graph....

A couple of manufacturers are selling solutions to speed up your big HDD using a relative small SSD. There are techniques like: Smart Response Technology (SRT) by Intel (hardware solution, Write-back) Dataplex by Nvelo (Windows, software, Write-back) ReadyCache by SanDisk (Windows, software, Writethrough) FancyCache by Romex Software (Windows, software) But there is also a lot of development on the Linux front. There is Flashcache developed by Facebook, dm-cache by VISA and bcache by Kent Overstreet....

An interesting thing happened last week when I upgraded qemu-kvm from version 0.12.5 (Debian Squeeze) to 1.1.2 (Debian Wheezy). After a reboot (shutdown and start) of all my VM’s, they are using less CPU in total! I noticed this from the stats Collectd is collecting for me. I’m running about 5 Debian Linux VM’s on my low power home server (Intel G620, 8G DDR3, DH67CF). Most of the time the VM’s are idle....

Since a while I’ve been monitoring the power consumption of devices in my home using a power meter from BespaarBazaar.nl (advised by Remi). This power meter is a good one because it is very precise. It starts measuring at 0.2 Watt. I needed an Ethernet switch to connect my TV, NMT and PS3 to my home network. While searching for a proper switch, I came across DLinkGreen.com. It looked promising. The Green Calculator, a 8....

Bonnie++ is the perfect tool to benchmark disk I/O performance. When you want to run heavy disk I/O consuming applications on a server, you need to know what the disk I/O limits are to have an indication what you can run on it. Bonnie gives you information about read-, write-, rewrite Block I/O performance and the performance of file creation and deletion. Below is a sample piece of Bonnie++ output. It is hard to read, and when you’ve done a couple of runs on different hosts, it’s hard to compare these results....