When you need to debug kernel behavior without full instrumentation frameworks, module parameters offer a pragmatic shortcut. Rather than immediately reaching for perf, kprobes, or eBPF, you can add simple toggles and state tracking directly in the code you’re investigating, then control them at runtime through sysfs. Frameworks like perf, kprobes, and eBPF are powerful…
QEMU/KVM uses global locks to synchronize threads, which is necessary for correctness but causes performance problems at scale. When multiple I/O requests and vCPU threads contend for the same lock, you get lock contention that manifests as scheduling jitter, reduced system scalability, and degraded I/O performance. IOThreads (the modern implementation of dataplane) address this by…
Running commands across multiple servers is fundamental to cluster management and infrastructure automation. While orchestration tools like Ansible and Terraform dominate modern deployments, sometimes you need lightweight solutions that work without dependencies—or you’re already invested in SSH-based infrastructure. When managing clusters, you typically work in two modes: serial execution (one node at a time) and…
Before writing code, get comfortable with fundamental Linux commands. You’ll use these daily: File operations: ls, cd, cat, less Text search: grep, ripgrep (rg) Remote access: ssh, scp, rsync Session management: tmux or screen for persistent terminal sessions Shell: bash (default on most distributions), though zsh and fish are popular alternatives Start with built-in documentation….
Hadoop 2.x reached end-of-life in 2016. This guide covers setup for learning purposes and legacy system maintenance only. For production deployments, use Hadoop 3.x or later, which includes performance improvements, better YARN scheduling, HDFS erasure coding, and improved security. Cloud-managed options like AWS EMR, Google Dataproc, and Azure HDInsight eliminate most operational overhead. This guide…
By default, WordPress displays full post content on index, category, tag, archive, and search pages. This duplicates content across multiple URLs, dilutes SEO value, slows page rendering, and forces readers to scroll through complete posts when they’re just scanning headlines. Using excerpts instead improves page load times, reduces crawl budget waste, consolidates ranking signals to…
KDE Plasma 6 provides straightforward touchpad configuration through the graphical Settings interface, with optional command-line customization for advanced cases. GUI Configuration Navigate to System Settings → Input Devices → Touchpad. You’ll find the “Tap to Click” toggle under the “Tapping” section. Enable it to map single-finger taps to left-button clicks. Additional options here include: Tap-and-drag:…
Package Installation Install the required packages: dnf install nfs-utils nfs-utils includes both server and client tools. The separate rpcbind package is no longer needed on modern systems — it’s handled as a dependency and runs as part of the NFS service. Configure /etc/exports Edit /etc/exports to define which directories clients can mount and with what…
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…
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 … | | | | |…