Using the FreeBSD RACK TCP Stack

Did you know that FreeBSD has more than one TCP stack and that TCP stacks are pluggable at run time? Since FreeBSD 12, FreeBSD has support pluggable TCP stacks, and today we will look at the RACK TCP Stack. The FreeBSD RACK stack takes this pluggable TCP feature to an extreme: rather than just swapping the congestion control algorithm, FreeBSD now supports dynamically loading and an entirely separate TCP stack. With the RACK stack loaded, TCP flows can be handled either by the default FreeBSD TCP stack or by the RACK stack.

Achieving RPO/RTO Objectives with ZFS

Today, let’s talk a little bit less about technology itself, and a little bit more about business management. There are a couple of key management terms that every system administrator and IT professional should know and love—RPO and RTO, or Recovery Point Objective and Recovery Time Objective.
Once we understand the meaning and importance of RTO and RPO, we will take a look at two ZFS technologies—snapshots and replication—which greatly ease their management.

Let’s Talk OpenZFS Snapshots

Understanding which data benefits from being in a snapshot and how long it makes sense to keep snapshots will help you get the most out of OpenZFS snapshots. Pruning snapshots to just the ones you need will make it easier to find the data you want to restore, save disk capacity, and prevent performance bottlenecks on your OpenZFS system.

FreeBSD TCP Performance System Controls 

While new protocols are constantly being developed, the venerable Transmission Control Protocol (TCP) still accounts for most global traffic. The FreeBSD kernel TCP stack offers a lot of opportunities to tweak different performance features. The options it includes allow a lot of flexibility in the configuration of machines without having to do custom kernel builds.
Find out how to make use of the Initial Window, what the TCP Segment OffLoad is, and how to use TCP Buffer Tuning to your advantage.

Managing Boot Environments

A ZFS boot environment is a bootable clone of the datasets needed to boot the operating system. Creating a BE before performing an upgrade provides a low-cost safeguard: if there is a problem with the update, the system can be rebooted back to the point in time before the upgrade.
This article demonstrates how to use the bectl utility to manage BEs and provides examples on how to update packages, apply security patches, and upgrade the operating system using BEs.

History of FreeBSD – Net/1 and Net/2 – A Path to Freedom

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Let’s talk some more FreeBSD history. From the release of 4.3BSD to how networking for all became available and Net/1 and Net/2 came to be.
This article is going to cover the time period from the release of 4.3BSD with TCP/IP to the BSD lawsuits. This period set the stage for BSD as we know it today.

FreeBSD Performance Observability

Performance observability

Performance observability is a powerful feature that highly supports FreeBSD. In this article, we’re showing you how to take advantage of tools that are specifically built for and with an operating system: tools which understand and are built into the operating system’s kernel structures. Learn about how to gather the information you need in order to get the most out of your system, determine your operational baselines, and find and resolve performance bottlenecks.

DTrace Network Probes

DTrace landed in FreeBSD 7.1 in 2009. DTrace is an observability framework that enables dynamic tracing of programs, and the FreeBSD Kernel. It offers an incredible view into the operation of programs, and is an excellent tool for debugging and performing analysis of complex software. Using the full power of FDT probes requires familiar knowledge with how things are implemented. SDT probes and specific providers like ip, tcp and udp offer insights into the internal behavior of the kernel without requiring a high level of knowledge of the underlying code.

Building Customized FreeBSD Images

Did you know that Poudriere is not only a package building tool for FreeBSD, but it can also generate FreeBSD images? You can also use NanoBSD or, perhaps, assemble a bootable FreeBSD image by hand. This article will explore some of the ideas and tools required to start down the path of building customized FreeBSD images, and by the end you should have the knowledge required to continue on your own.

Deep Diving Into the Strengths of FreeBSD

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FreeBSD brings forward advanced networking, performance, security and compatibility features that are still missing in many other operating systems. Its focus on performance, networking, and storage, its ease of system administration, and its overall integration are features that make it the right choice for many applications. In this write-up, we list some of the strengths that make FreeBSD a powerful operating system.