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About Jan

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So far Jan has created 19 blog entries.
17 06, 2024

Optimizing Linux Swappiness: Lessons from Upgrading to RHEL 8

By |Categories: Best Practices, How to|

As part of our continual improvement process we have been migrating our RedHat Enterprise Linux 7 and alternatives over the last few years. With version 7 being end of life by 30th of June 2024, the last machine running this version are being swapped for the more recent and actively maintained version 8. We will describe the roll-over of the various systems in some detail and focus on one particular topic that had us scratching our heads for a while.

Migrating always starts with a good plan

First step is to notify the customers that an upgrade to their server is needed.

07 11, 2022

Popular Web Hosting Tools show not to provide a full-native script experience yet

By |Categories: How to|Tags: , , , , |

Web hosting tools enable people and organizations to have a website accessible on the Internet. They rely on web servers, email servers and backend databases to provide the building blocks of a website’s functionality in the digital world. The question is do they provide seamless experience for users using internationalized email or using a new localized top-level domain (TLD)?

Together, the Universal Acceptance Steering Group (UASG) and Nexperteam conducted a study to assess to what extend three of the most widely used web hosting tools, cPanel, Plesk, and ISPConfig offer the capacity for customers to build websites and host emails

26 02, 2021

GDPR, Cookie-policy, Whatever

By |Categories: How to, Security|

By default, I try not to rant about things. I try to be as truthful and complete as possible. I try to be informed. I try to give sound advice based on the knowledge I have and be open for alternative idea.

Nevertheless, often whatever you do, you encounter something that is so mind-boggling bend you could just say what need to be said and be done.

Being European-based, GDRP is a hot topic. It is so hot that many opinions have formed and it feels like everyone with a legal background seems to have some solution and some problem that is

08 02, 2021

A tech perspective on what cloud truly is

By |Categories: Cloud Migration|Tags: |

We on-boarded a new guy recently. He called himself a blank canvas but we know that this is not true. However, it brings us back to explaining the basics. One of the most basic questions turns out to be quite deceiving. What is Cloud?

One of our coworkers shared an article on Cloud Flair, which explains that Cloud is about two basic things: not owning your own hardware and virtualization. Next, they bring in all the buzz words: IAAS, PAAS and SAAS to end up with FAAS. Running everything As-A-Service, Infrastructure, Platform and Service to end Functions. Nice, we have all

12 01, 2021

Performance and where it all can go wrong

By |Categories: Best Practices, How to, Security|Tags: , |

Modern web applications come with a complex set of underlying services. When the applications are not performing and the response time to deliver a page is high, the search to track the problem down starts.

In this article, we’ll go through performance on different levels of delivering a web page to the browser and we’ll provide an example of troubleshooting performance issues.

Performance on different levels

Understanding why a web page under-performs is seldom easy. Let’s have a look at what actually happens when things get slow. Understanding the full process of delivering a web

28 12, 2020

Creating happiness with a few lines of code

By |Categories: How to|

We all love making people happy. And happiness sometimes comes with just that little bit of extra help. Recently we had a request for the simplest thing you could possibly imagine. One of our coworkers wanted something that converted a set of lines into an excel file. The import capabilities of excel are virtually limitless. But that doesn’t mean that the tools are always easy to use.

Let’s analyze the problem. So we have a list of lines where every line has to be in a separate excel cell. Good. And when does

21 12, 2020

Security and obscurity

By |Categories: Best Practices, Security|Tags: , |

It is unfortunate that talking about security is still deemed dangerous. The idea is that if you do not share the information it will be harder to find the security hole. The opposite is true as well. By not talking about how things work, people start assuming. This inevitably leads to many problems and is often the start of many security problems that go undetected.

Let’s have a look at a very concrete example.

Two-factor authentication

Not so long ago, the one and only barrier grant someone access to an application was the typical “user

03 12, 2020

How to deal with cloud databases and network latency

By |Categories: Best Practices, Cloud Migration, How to|Tags: , |

“We moved our database into the cloud and it was terrible”. Or wasn’t it?

When we started moving a large database into the cloud we drafted a migration scenario to minimize the downtime. Migrating from one type of database to another one is seldom an easy game. Combine this with the fact the there was a lot of data to be shipped and you can understand the raw complexity.

We managed to set up an incremental process that on the first run would take several days, the second run about a day and then

25 11, 2020

To Cloud or not to Cloud

By |Categories: Cloud Migration|Tags: |

When it comes to the infrastructure we are living interesting times. Big cloud providers are fighting to get a piece of the cake and make it as big as possible by bolting additional services to it. The process of mergers and acquisitions has been going on for a number of years and now that BigTech is trying to corner the market we will see more consolidation.

We estimate the end result to be a handful of players trying to focus on specific areas and gain as much market share as possible. For example, IBM focuses on AI & NLP, Google on

17 11, 2020

NTP Troubleshooting

By |Categories: How to|Tags: |

When it comes to our on-premise cloud infrastructure we are old school. We use a RedHat RHEV visualization stack and a GlusterFS storage stack. It’s a pretty nifty setup and one can hardly call it outdated. It has been up and running for several years now with little problems.

Monitoring the infrastructure and taking care of small errors when they occur will ensure that our infrastructure is resilient and stable.

In this post, we’ll share a few insights into how we troubleshoot an NTP issue which was undercover as a network stack issue.

NTP time service

To make sure that all our machines run

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