Welcome to It-Slav.Net blog
Peter Andersson

I've already got a female to worry about. Her name is the Enterprise.
-- Kirk, "The Corbomite Maneuver", stardate 1514.0

Andreas Ericsson at op5 is working with major improvements of Nagios. The focus areas are:

  • Complexity reduction by moving from multi-threading to single threaded programing
  • Reducing latency
  • Disk I/O usage reduction
  • CPU usage reduction
  • Memory usage reduction

Read more at http://blogs.op5.com/development-work-on-nagios-project-to-improve-performance/

Filled Under: Nagios, op5, op5 Monitor


On my electricity meter I have a flashing LED. 1000 flashes is 1 watthour.

As a monitor geek I want to know my powerconsumption and find a 1-wire kit containing a counter and a sensor that could detect the flashing from the electricity meter.

I wrote a script that collect the data in an RRD database and graph it. 




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I have a FON router which allow anyone to connect to Intenet via my network connection. I like the openess and idea behind FON but I do not want to get in trouble if someone do bad things and using my network connection.

One solution is to connect the FON accesspoint to a separate network segment and let all traffic from that network go through TOR, the onion router. 

Another feature is when I want to be anonymous on Internet I plugin my computer to that network segment.

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It really annoyed me that the iowait at the cpu on the Dom 0 system was approximatly 50% when the 4 virtual system was doing more or less nothing.

I showed my earlier blogpost about VM virtualization to our sysadmin at op5. He gave me a couple of more hints that really make a big difference, the best part is that they are real simple to implement.

I also noticed that I forgot some parts in the previous article that was obvius to me.

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As an it slave, I have the same problems as most datacenters:

  • Running out of space because of more and more machines get into the datacenter
  • Overheating
  • Powerconsumption

Added to the "normal" datacenter problems, I also have to deal with:

  • Wife acceptance
  • Noice, my neighbours has complained about the noice outside my basement.

To address this issues I will run a consolidation project to get fewer machines by using virtualization. As virtualization engine, KVM is choosed.

This article will describe some pitfalls I run into and how I solved them.

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After a couple of weeks fiddeling I can prodly announce that my new internet connection is in full use.

The new access speed is 100 Mbit/s optical fiber, iperf tests show that I can get approx 97 Mbit/s in booth directions.


  • 100 Mbit/s internet access provided by Ownit
  • Updated firewall to OpenBSD 5.0 running on an Astaro appliance
  • Updated Webserver to Centos 6.2, virtulized with KVM
  • Updated Mailserver to Centos 6.2, virtulized with KVM


Happy new year


 News – Monitor v5.5

Monitor 5.5 –  It’s always extra fun when we do releases. News in short are:

  • Support for offline maps – no need to have online gmap connection
  • Introducing IP traffic “weathermaps” i.e. a user friendly way to present traffic flows, being WAN or LAN traffic
  • Display monitor data on external web i.e visualise and distribute the information to greater crowd
  • Multiple of  time saving tasks such as multidelete, free text filter, save searches etc.

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 Nov 1, 2011.

We are pleased to announce the official release of OpenBSD 5.0.
This is our 30th release on CD-ROM (and 31th via FTP).  We remain
proud of OpenBSD's record of more than ten years with only two remote
holes in the default install.
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Filled Under: OpenBSD, sysadmin
The tech team at op5 have published a number of new How-To articles on the op5 Support
web. Here is a list of the most recent How-Tos:
Access op5 Monitor from your iPhone
Access op5 Monitor on Android Smartphone
How-to monitor a KVM installation
Secure communication with Cloud poller
Agentless Monitoring of Windows using WMI
How to monitor your application server with op5 Monitor and JMX4Perl
Please let me know if you have any suggestion for future How-To articles.

My internet connection is a crappy ADSL line.


I noticed that I did get alot alerts from op5 Monitor complaining about high error rate on the external network. After some investigation I noticed that UDP port 5060 generated approx 1.5 Mbps in traffic and that is more or less maximum my ADSL connection can handle. UDP port 5060 that is SIP.


A nice graph showing the errorrates, generated by op5 Monitor:

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Book reviews
FreePBX 2.5
Powerful Telephony Solutions

Asterisk 1.6
Build a feature rich telephony system with Asterisk

Learning NAGIOS 3.0

Cacti 0.8 Network Monitoring,
Monitor your network with ease!