Project Stalwart - mail & collaboration server

Stalwart is an open-source mail & collaboration server with JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV and WebDAV support and a wide range of modern features.

https://stalw.art/ 

https://stalw.art/docs/install/platform/docker/ 

https://github.com/stalwartlabs/stalwart

Project Coriolis - V2V, P2V, V2C, P2C Tool

Coriolis is Cloud Migration as a Service.

Migrating existing workloads between clouds is a necessity for a large number of use cases, especially for user moving from traditional virtualization technologies like VMware vSphere or Microsoft System Center VMM to Azure / AzureStack, OpenStack, Amazon AWS or Google Cloud. Furthermore, cloud to cloud migrations, like AWS to Azure are also a common requirement.

You can find further information about the project Coriolis at GitHub - https://github.com/cloudbase/coriolis

Exos 4U74 and 4U100

I often build Software-Defined Storage systems, which require robust hardware with both high performance and large capacity. I have recently found that Seagate has ultra-dense SAS-4 JBOD systems combining next-gen Mozaic drive readiness with energy-efficient design for AI, edge, and sovereign data infrastructure. It supports up to 3.2PB in a single 4 RU enclosure.

Here are few pictures ...

 

AI Servers and Racks

I’m trying to explain that an AI Factory truly functions like a factory, and that it is a fundamentally different discipline from a traditional datacenter.

A picture is worth a thousand words, just look at the photos below. 

Ohm’s Law Analogies for Modern IT Infrastructure Performance

In electrical engineering, Ohm’s law is one of the cleanest and most intuitive relationships:

$$$$U = I x R

Voltage pushes current; resistance slows it down. But can we find something similarly elegant in IT infrastructure?

Computers and networks are more complex than a simple circuit. However, several concepts in networking, storage, and CPU performance behave similarly to Ohm’s law and can be modeled using comparable relationships. Below are practical, engineer-friendly analogies you can use when sizing, troubleshooting, or explaining systems.

IT Fundamentals

Distinguished engineer Kelsey Hightower explores why understanding fundamentals matters more than chasing trends, sharing lessons from 25 years in tech at HAProxyConf. 

This is a very good video about IT fundamentals. It covers IT fundamentals, IT Infrastrucutre, and DevOps/Automation way how to do a clever IT.  He covers even AI hype with MCP and very correctly points to fundamentals. Every IT Engineer should see this video.  

Series and parallel battery wiring

Battery systems often rely on combining multiple cells, but how you connect them determines the final voltage, current, and capacity. Series and parallel wiring follow simple electrical rules, yet they lead to very different behavior under load. This brief post will walk through the core differences so you can understand the impact of each configuration.

Ghost Hunting in Infrastructure: The Art of Troubleshooting Micro-Bursting

In the video below, Robert Vojčík delivers an excellent talk about troubleshooting, “ghost hunting,” and the realization that the more we know, the more we understand how much we don’t know - a timeless truth that goes back to Socrates.

Author: Robert Vojčík

Date: Oct 10, 2023

YouTube Video Name: Jak sme hladali TCP Timeouty v Kubernetes (aka micro-bursting)

URL: https://www.youtube.com/watch?v=-tlfdo99RxI

The presentation is in Slovak, but that shouldn’t be a problem, at least not in the present and future age of AI, when automatic English subtitles are just a few clicks away. And for those of us from the former Czechoslovakia, Slovak language feels natural anyway.

Airflow mode of Cisco Nexus 93180yc FX3

I need to rack and stack Cisco Nexus 93180yc FX3 in my datacenter, therefore, I need to know what airflow mode to choose.

The Nexus 9K datacenter switches support two airflow modes

1. Portside intake - sucks cold air into network ports and blows warm air out of the power supply's  into hot aisle ( red  release latch on hot-swap PSU)
2. Portside exhaust - sucks cold air into power supply's and blows warm air out of the ports into hot aisle ( blue  release latch on hot-swap PSU)

In my particular case, the network ports should be located on the same side of the rack as the server’s rear panel, therefore, I need portside exhaust airflow mode, therefore hot-swap PSU has  blue  release latch.

Hope this helps other IT guys in the field. 

IPv4 Addresses Cheat Sheet

Bellow is my cheat sheet about IPv4 addresses and sub-netting.

 

 

The cheat sheet is primarily for myself :-), but somebody else can find it helpful and use it.

Description: The math binary representation of IP octets (bytes) and relation to Net Subnetting.

Keywords: Class Addressing, Classless Addressing, Tips & Tricks