DNS caching helps reduce lookups but sometimes you need to clear it after DNS changes, certificate updates, or to troubleshoot resolution issues. Modern Linux with systemd-resolved Most contemporary Linux distributions use systemd-resolved as the default DNS resolver. Flush the cache with: sudo systemctl restart systemd-resolved Or use the resolvectl command: sudo resolvectl flush-caches To verify…
This article documents performance benchmarks for Xen virtualization, comparing CPU and memory performance between Dom0 (privileged domain), DomU (unprivileged guest), and bare metal. While Xen remains in production use (AWS EC2, Citrix Hypervisor, Oracle Cloud), most Linux distributions default to KVM for new deployments. For contemporary virtualization needs, evaluate both Xen and KVM based on…
Xen remains in active production use—particularly in cloud infrastructure like AWS EC2 and Citrix Hypervisor—though KVM has become the standard hypervisor for most Linux distributions. If you’re managing legacy Xen deployments, this guide covers the essential steps for cloning VBD-based DomU instances. Prerequisites Before starting, ensure: The source VM is powered off (critical to avoid…
Desktop clients for WordPress have largely fallen out of favor in recent years, but they still serve a niche purpose for users who prefer offline writing and batch publishing. Lekhonee was one such tool — a GNOME-based WordPress client that provided a lightweight alternative to the web interface. Important context: Lekhonee is no longer actively…
Keeping Thunderbird running constantly makes sense for monitoring incoming mail, but leaving it on the taskbar consumes screen real estate. System tray integration is cleaner—minimize to a small icon and optionally display unread message counts. Thunderbird’s addon ecosystem provides platform-specific solutions for this. Note that addon availability and compatibility can vary; check the Mozilla Addons…
When you open a Windows file in Vim (or Neovim), you’ll often see ^M characters at the end of lines. These are carriage returns (\r) from Windows line endings (CRLF), which don’t display properly on Unix-like systems that expect LF-only line endings. Quick Fix The fastest way to remove these characters is with a substitution…
Fedora 中文字体的显示一直是个常见问题，特别是在英文环境中。通过合理的字体配置，可以获得清晰舒适的中文显示效果。本文介绍的方案使用开源字体，这些字体在 Fedora 的标准仓库中都可以获得。 快速配置 如果你只想快速完成配置，运行以下命令： sudo dnf install cjkuni-ukai-fonts cjkuni-uming-fonts sudo wget https://raw.githubusercontent.com/zma/config_files/master/others/local.conf \ -O /etc/fonts/local.conf sudo fc-cache -vf 完成后重启应用或重新登录系统。 安装中文字体 在现代 Fedora 中，安装中文字体包非常简单： sudo dnf install cjkuni-ukai-fonts cjkuni-uming-fonts 这两个包提供的是 AR PL UMing 和 AR PL UKai 字体家族，效果清晰，特别适合显示器阅读。 安装完成后，更新字体缓存： sudo fc-cache -vf 配置字体优先级 字体配置文件应该放在 /etc/fonts/local.conf（系统级，需要 root 权限）或 ~/.config/fontconfig/fonts.conf（用户级）。 用户级配置创建 ~/.config/fontconfig/fonts.conf： <?xml version=”1.0″?> <!DOCTYPE fontconfig…
ISO images are sector-by-sector copies of optical media stored as binary files. They’re useful for archiving DVDs or creating portable copies without keeping physical disks around. On Linux, several tools can accomplish this—dd is the simplest, but modern alternatives offer better features. Using dd to Create an ISO Image The most straightforward approach uses dd:…
DNS lookups can be a bottleneck in Firefox browsing performance. Here are practical methods to optimize DNS resolution and related network behavior. Disable IPv6 (if not needed) If your network doesn’t use IPv6, disabling it can eliminate unnecessary lookup delays. In Firefox, navigate to about:config and set these preferences: network.dns.disableIPv6 → true This prevents Firefox…
The default number of loop devices on most Linux systems is 8, which is often insufficient for scenarios like running multiple virtual machines with loop device-backed storage, containerized environments, or disk image management. If you need more than the default allocation, you’ll need to increase max_loop. First, check your current loop device count: losetup -f…
To connect to HKUST’s sMobileNet wireless network via NetworkManager, you’ll need to configure WPA2 Enterprise authentication with PEAP. This guide covers the required settings. Network Settings Configure the following parameters in NetworkManager: Basic Settings: SSID: sMobileNet Wireless security: WPA & WPA2 Enterprise Authentication method: Protected EAP (PEAP) Authentication Details: Anonymous identity: (leave empty) PEAP version:…
Xen remains a robust hypervisor for production environments—AWS EC2, Citrix Hypervisor, and many hosting providers still rely on it. However, KVM has become the default for most Linux distributions due to simpler management and better integration with standard tooling. For new deployments on standard Linux, evaluate KVM with libvirt or container solutions like Docker and…
Configuring proper Chinese character rendering in Fedora requires attention to font selection and system settings. This guide covers configuration for contemporary Fedora/RHEL systems where you run an English locale but need reliable Chinese character display. Font Selection You have several solid open-source options for Chinese fonts. Each has different characteristics suited to different use cases….
Customizing your desktop environment to match macOS aesthetics remains popular on Linux, though the approach differs significantly from GNOME 2 era configurations. Modern desktop environments like GNOME (40+) and KDE Plasma (5/6) use different theming systems, but achieving an Apple-inspired look is still straightforward. Current Desktop Environment Options GNOME 40+ uses CSS-based theming and GTK…
Free virtualization on Linux has multiple solid options. While VMware Player is still available, QEMU combined with libvirt has become the standard approach for most sysadmins. This guide covers creating VM disk images and configurations that work across multiple hypervisors. Creating Virtual Disk Images The first step is creating a virtual disk. QEMU’s qemu-img tool…
Mounting an ISO on Linux requires a loop device. Modern systems support this directly with mount: sudo mount -o loop /path/to/image.iso /mnt/mount-point Or use the -t iso9660 option for explicit filesystem specification: sudo mount -t iso9660 -o loop /path/to/image.iso /mnt/mount-point To unmount: sudo umount /mnt/mount-point For temporary mounts that don’t require persistence across reboots, consider…
Crontab controls what runs and when. Each crontab entry has this format: .—————- minute (0-59) | .————- hour (0-23) | | .———- day of month (1-31) | | | .——- month (1-12) OR jan,feb,mar,apr … | | | | .—- day of week (0-6) (Sunday=0 or 7) OR sun,mon,tue … | | | | |…
File compression is a routine task in Linux administration. You’ll encounter several tools, each with different tradeoffs between compression ratio, speed, and compatibility. This guide covers the most common compression formats: gzip, bzip2, 7z, xz, and zip. The examples below assume you’re compressing a directory called dir. Each tool supports compression level options — you…
Modern datacenters rely on distributed storage and processing systems designed to handle massive datasets across clusters of commodity hardware. Understanding these systems is essential for anyone working with infrastructure at scale. Here’s an overview of the major architectures and implementations you’ll encounter. Storage Systems Google File System (GFS) and successors GFS established the foundation for…
Colossus is Google’s successor to the Google File System (GFS), designed to handle the massive scale of data storage across Google’s infrastructure. While GFS was documented in detail in the 2003 SOSP paper, Colossus information remains sparse in academic literature—much of what we know comes from talks and interviews with Google engineers. Colossus serves as…