Klaus Aschenbrenner

Maximizing 40G NIC Performance on Linux with Intel XL710 and Cisco Nexus Switches

06/16/2025 / By / Linux, Performance Tuning / Leave a Comment

In this comprehensive technical walkthrough, I’ll take you through a real-world journey of troubleshooting and tuning a high-performance 40 Gbit Ethernet setup using Intel XL710 network cards connected through a Cisco Nexus 3064 switch. The goal was simple but challenging: to achieve near line-rate performance using iperf3 between two Linux (Proxmox) systems. When I first started testing …

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From SQL Server to PostgreSQL: A Story of 5 Key SQL Differences

06/11/2025 / By / PostgreSQL, SQLServer / 2 Comments

After spending decades working in SQL Server, getting familiar with PostgreSQL felt like traveling to a country where everyone speaks a language I mostly understand – but with a different accent and some unfamiliar slang. At first glance, SQL is SQL. But once I started writing real queries in PostgreSQL, I realized that my habits from T-SQL …

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Why I Created the SQL Rescue Sprint – And How It Works

06/04/2025 / By / Performance Tuning, SQLServer / Leave a Comment

Over the past 25 years, I’ve worked with SQL Server in all kinds of environments: startups, mid-size companies, and global enterprises. And no matter the industry or infrastructure, one thing is always true: When SQL Server slows down, everything slows down! Reports take forever. Blocking brings processes to a halt. Deadlocks frustrate both users and …

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Solar-Powered, Proxmox-Driven: A Tour of My Ultimate SQL Server Home Lab

05/12/2025 / By / Computer Science, SQLServer / 4 Comments

Back in 2018, I wrote a blog post about my Home Lab environment, which I had built around VMware vSphere to showcase various SQL Server workloads and demonstrate how to troubleshoot performance-related problems. Since then, a lot has changed – especially with the acquisition of VMware by Broadcom. In the past, I was a subscriber …

Solar-Powered, Proxmox-Driven: A Tour of My Ultimate SQL Server Home Lab + read more

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