As the winter chill sets in, we’re warming things up with a special holiday roundup that explores problem-solving, featuring stories and guides that showcase the investigative work Klara has done on OpenZFS and FreeBSD. Whether you're a seasoned sysadmin or just exploring OpenZFS and FreeBSD, these stories will equip you to tackle your next technical challenge with confidence and insight.

OpenZFS

📈 Cracking the Code on ZFS Performance Bottlenecks

Sometimes, the issues impacting performance are hidden in our own configurations or workloads, silently impacting performance without obvious signs. From misaligned writes, to unexpected fragmentation, the ZFS Performance Optimization Success Stories article highlights some of Klara’s most intriguing ZFS performance investigations and the solutions that delivered results.  

🛠️ Rescuing Systems: From Recovery Mode to Normal Operations

Not all investigations are about optimization—sometimes, the task is simply to bring a system back to life. Our final ZFS article, Manipulating a Pool from the Rescue System, takes you through the essential steps of troubleshooting and recovering a FreeBSD system using OpenZFS. From single-user mode to live recovery, this guide gives you the tools to handle even the toughest boot failures with confidence. 

   | Need expert help with bug investigation? Our experienced team is available to investigate and patch OpenZFS bugs, ensuring data integrity and optimizing performance. 

🔧 Tackling the ZFS Data Corruption Bug

Data corruption bugs are rare but critical. In the “HOLEy ZFS" podcast episode of the 2.5 Admins podcast, Jim and Allan break down the details of the Thanksgiving 2023 ZFS data corruption bug, and give their tips for managing a fleet of 40+ servers. 

🔍 The ZFS Puzzle: Cracking a Petabyte Recovery Case

When disaster struck a massive ZFS pool, Allan Jude and his team were tasked with restoring order. The “A Chat about Linus' DATA Recovery" episode of Level1Techs podcast episode examines the technical process of recovering Linus Tech Tips' data, addressing issues like failing drives, backplane failures, and ZDB recovery techniques. Tune in to gain valuable insights into handling critical ZFS recovery challenges and preventing data loss in the future. 

   | Want to hear some more spine-chilling ZFS tales? Check out our recent webinar on OpenZFS Horror Stories, where Klara’s Allan Jude and JT Pennington share real-life cases of data recovery challenges and lessons learned. 

FreeBSD

Switching gears, for those working with diverse and challenging network conditions, Dummynet is a critical tool for network emulation and traffic shaping. 

🌐 Dummynet: The Better Way to Build FreeBSD Networks 

Ever wonder how your applications would perform in the real world under tough network conditions—like a satellite connection with 300ms latency or a congested edge network with packet loss? The The Better Way to Build FreeBSD Networks article explores Dummynet's powerful features, from emulating bandwidth limits to shaping traffic with precision, bringing the real world into your lab.  

📊 Packet Scheduling with Dummynet and FreeBSD

Building on the foundation of network emulation, the second part of our Dummynet series, Packet Scheduling with Dummynet and FreeBSD  focuses on packet scheduling. Learn how to manage traffic effectively with Dummynet’s advanced algorithms, prevent congestion, and ensure smooth performance even in high-demand scenarios. 

🌐 🔍 FreeBSD Network: Investigate Performance Like a Pro

Building networks with Dummynet gives you the tools to emulate, shape, and schedule traffic in diverse environments. But once your network is live, the challenge shifts to investigating its real-world performance. The FreeBSD Network Troubleshooting: Understanding Network Performance article walks you through the intricate relationship between delay, bandwidth, and protocols, equipping you to ensure your networks perform optimally under any load. 

🛡️ Investigating Security Vulnerabilities in FreeBSD 

With network performance under control, it's time to turn your attention to system security. In Using FreeBSD’s pkg audit to Investigate Known Security Issues, we cover tools for identifying and addressing vulnerabilities. From auditing the Base System to checking third-party packages, this guide equips you with the knowledge to stay ahead of security risks. 

🌌  The 20 Year Old Bug That Went to Mars 

Some mysteries span decades—and even planets. The “Audit That Package" episode of the BSD Now podcast reveals the 20-year-old integer overflow in the LZO algorithm, which stealthily made its way from Earth to NASA's Mars rovers. Plus, the BSDNow crew explore FreeBSD's pkg-audit for proactive security, Slimbook optimizations, and new LLDB kernel dump support, along with a few obscure but awesome X11 tools to level up your workflow. 

🎯 Catch a Bitcoin Miner: A Sysadmin’s Detective Tale 

Our final investigation in this roundup starts with a curious spike in CPU activity—a signal that something wasn’t quite right. What followed was a focused hunt for a rogue Bitcoin miner hiding in plain sight. Our How to Catch a Bitcoin Miner article takes you behind the scenes of a sysadmin’s effort to uncover and neutralize the threat, blending technical expertise with a detective’s eye for detail. 

   | Curious to hear more untold stories from silent FreeBSD users? In the Supporting FreeBSD in the Field talk at BSDCan, Allan Jude shares compelling stories of FreeBSD deployments in industries where users rarely discuss their challenges or successes. 

Happy Reading this Winter!

Investigation is at the heart of every great technical achievement, and this roundup highlights just how far curiosity and expertise can take us. 

With this winter holiday collection, you’ll gain actionable insights into OpenZFS and FreeBSD investigations—from cracking performance bottlenecks to tackling security vulnerabilities and debugging complex issues. 

Happy holidays from all of us at Klara - stay tuned for new content and  upcoming webinars!