Linux / Unix Q & A and HowTos For Advanced Users

Advanced Linux, macOS, *BSD, and Unix-like tutorial {Q & A} for developers, sysadmins, and IT security folks. You can get the latest tutorial using the RSS/XML feed or weekly newsletter.

When working with FreeBSD and ZFS, you will run into ZFS cache size problems. Not all FreeBSD servers are file servers. Some servers act as backup servers. Others might run Linux and Windows VM where you want those guest VMs to manage their own caching. It would help if you had tons of RAM for ZFS, but you may not have that luxury in real life. This page explains how to set up ZFS arc size on FreeBSD to work with less RAM to avoid the computer running out of memory in the kernel.
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Typically, we apply firmware updates to fix a security issue and enhance SATA/PCIe/NVMe solid-state (SSD) drive performance. Failing to install available updates may lead to vulnerable SSD. This quick guide explains how to update Samsung SSD firmware on Linux without using Windows operating system.
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Alpine Wall (Awall) is an easy to use interface to iptables for Alpine Linux users. While iptables and ip6tables is an excellent command, it can be challenging for new Alpine Linux users. The awall tool has easy to follow high-level concepts such as zones, limits, policies, and a single source for both IPv4 and IPv6. This tutorial will show you how to set up a firewall with Awall on Alpine Linux.
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