LVM snapshots provide a fast, efficient way to duplicate virtual machines across servers. This technique applies to any LVM-backed hypervisor including Xen, KVM, and Proxmox. The process uses LVM snapshots on the source server, then transfers the snapshot image to the destination using standard Unix tools. Scenario Source server: 10.0.0.10 with VM stored in /dev/vg_xen/vm-10.0.0.123…
Xen remains a production hypervisor used by AWS EC2, Citrix Hypervisor, and other cloud providers, though most general-purpose Linux distributions have shifted toward KVM as their default. If you’re working with Xen in production or developing drivers, understanding its source code layout is essential. Top-Level Directory Structure The Xen source repository (hosted on xenbits.xen.org) is…
LVM snapshots provide an efficient way to duplicate virtual machines in seconds rather than minutes. Instead of copying an entire filesystem, snapshots leverage copy-on-write semantics—physical blocks are only duplicated when the source or snapshot is modified. This approach works well for any LVM-backed virtualization platform, though Xen is used here as an example. Note: Xen…
LVM logical volumes are a practical choice for Xen guest storage. They support dynamic resizing, snapshots, and efficient cloning — capabilities that make capacity management and guest provisioning straightforward compared to fixed disk images. This guide covers creating and configuring LVM-backed virtual block devices (VBDs) for Xen DomU instances. Creating the logical volume Start with…
The firmware (BIOS/UEFI) on your system contains critical hardware settings and boot information. Knowing your firmware version is essential for updates, compatibility checks, and troubleshooting. Here’s how to find it. Using dmidecode dmidecode is the standard tool for reading the Desktop Management Interface (DMI) table, which stores hardware and firmware metadata. Most distributions include it,…
Building and maintaining Linux clusters requires coordinated management of user accounts, storage, networking, and services across multiple machines. This guide covers practical approaches to common clustering challenges, from unified authentication to network isolation. Account and Storage Management Unified Authentication and Home Directories Centralizing user management across cluster nodes eliminates the overhead of maintaining individual user…
A Fedora Live USB lets you boot directly into a Fedora environment without modifying your hard drive. You can use it to test Fedora, troubleshoot your system, or perform a fresh installation. This guide covers modern tools and workflows for creating bootable USB media. Back up any data on your USB stick first — the…
GNOME has hidden a few playful easter eggs in its desktop environment over the years. Two of the most well-known are “Free the Fish” and “Wanda the Fish” — small animated features that surprise unsuspecting users. Free the Fish (GNOME 2) In GNOME 2, pressing Alt+F2 and running this command: free the fish releases a…
Xen remains a production-grade hypervisor used in enterprise environments (AWS EC2, Citrix Hypervisor), though KVM has become the default for most Linux distributions. This guide covers building a stable Xen Dom0 on current Fedora releases using modern kernel sources. Hardware Considerations This guide assumes server-class hardware with: Intel or AMD processor with virtualization extensions (VT-x…
This post covers Xen virtualization benchmarks from 2013. While Xen remains in production use (AWS EC2, Citrix Hypervisor), KVM has become the default hypervisor for most Linux distributions. For current production environments, evaluate KVM with libvirt, direct container solutions (Docker, Kubernetes), or cloud-native platforms. This post is preserved for historical reference and understanding legacy Xen…
Xen remains a critical hypervisor in production environments—AWS EC2, Citrix Hypervisor, and other cloud platforms rely on it—but most Linux distributions now default to KVM for general-purpose virtualization. If you’re working with Xen specifically, this guide covers Dom0 and DomU setup on modern distributions. When to Use Xen Xen is worth considering if you need:…
Xen remains relevant in production environments (AWS EC2, Citrix Hypervisor), though KVM has become the default for most Linux distributions. This guide covers frequent installation and configuration issues specific to Fedora Dom0 setups, with many tips applicable to other Linux platforms. BIOS Configuration If Xen fails with “I/O virtualization disabled,” you need to enable virtualization…
Linux provides multiple ways to query network configuration. While the underlying concepts remain consistent, modern tools have evolved from the older net-tools utilities. IP Address, MAC Address, and Netmask The modern replacement for ifconfig is ip addr: $ ip addr show This displays all network interfaces with their IPv4 and IPv6 addresses, MAC addresses, and…
To find all available versions of a package in your repository, use the –showduplicates flag: dnf list –showduplicates kernel Or for other packages: dnf list –showduplicates <package-name> The output shows both installed and available versions with their release tags. For example: Installed Packages kernel.x86_64 6.8.1-1.fc39 @updates Available Packages kernel.x86_64 6.7.12-200.fc39 updates kernel.x86_64 6.6.25-1.fc39 updates kernel.x86_64…
Xen remains production-grade virtualization for specific use cases (AWS EC2, Citrix Hypervisor), but most Linux distributions default to KVM. This guide covers Xen DomU setup using modern tools and practices. For new deployments, evaluate KVM/libvirt or container solutions like Podman/Kubernetes first. Storage Setup Create a file-backed virtual block device (VBD) for your DomU. File-backed storage…
This post documents jailbreaking procedures for legacy iOS devices (iPod Touch, early iPhone) using Spirit—an untethered jailbreak tool from the late 2000s. Modern iOS devices (2010 and later) use entirely different security models and jailbreak methods. This information is preserved for historical reference only and has no practical application to current iOS versions. About Spirit…
When using KDE Plasma with GTK applications, you’ll notice the mouse cursor switches to a default style when moving from the desktop to applications like Firefox or GIMP. This happens because GTK and Qt use separate cursor theme configurations by default. Quick Fix The easiest solution is to explicitly configure GTK to use your chosen…
If you prefer booting to a minimal environment and starting your desktop manually, you can configure startx to launch KDE Plasma instead of your default desktop environment. Understanding startx and Desktop Selection The startx command reads configuration files to determine which desktop environment to start. On systemd-based distributions (Fedora, RHEL, Arch), the startup chain typically…
Modern Linux distributions typically auto-detect and load NVIDIA drivers without requiring manual xorg.conf configuration. However, if you’re using an older setup with an explicitly configured xorg.conf file, or if you need to customize NVIDIA driver behavior, you can disable the NVIDIA logo that displays during X server startup. Modern Approach (Wayland/Systemd) On current distros using…
MAC stands for Media Access Control — a six-byte identifier (usually written as twelve hexadecimal digits) that uniquely identifies a network interface on a LAN. The Address Resolution Protocol (ARP) maps IP addresses to MAC addresses at layer 2. You might need to change your MAC address to: Bypass network access controls tied to MAC…