Benchmarks exist to answer one question: how fast can this system process data? The AMPLab Big Data Benchmark, developed by UC Berkeley, became a foundational effort to answer that question systematically across different distributed query engines. The Benchmark’s Original Scope The AMPLab benchmark evaluated five systems circa 2013: Redshift – Amazon’s columnar data warehouse (built…
Sending email notifications when commits are pushed to a central Git repository helps teams stay coordinated and maintains audit trails. This is handled through Git hooks—scripts triggered by repository events. How Post-Receive Hooks Work When a client pushes to your Git server, the post-receive hook executes automatically. This hook lives at GIT_DIR/hooks/post-receive in your bare…
Gitolite provides fine-grained access control over Git repositories without the overhead of a full-featured platform. It uses SSH keys for authentication and handles per-user, per-repository, and even per-branch permissions through a simple configuration file. This guide covers a working installation on modern Linux distributions. Prerequisites Server: Linux (Ubuntu 20.04 LTS or later, Debian 11+, RHEL/Rocky…
Fedora is a cutting-edge distribution sponsored by Red Hat that serves as a testing ground for technologies eventually stabilized in RHEL. This guide covers essential infrastructure, system administration, and desktop tools for modern Fedora systems, with practical installation and usage examples. Desktop Environment Setup GNOME Configuration Modern GNOME desktops (GNOME 40+) use dconf for configuration,…
VNC provides graphical remote access to Linux servers. For security, tunnel VNC traffic through SSH rather than expose it directly to the network. This guide covers Windows client setup with SSH tunneling. Prerequisites Windows client: SSH client: Native OpenSSH (built into Windows 10/11) or PuTTY VNC viewer: RealVNC Viewer, TigerVNC Viewer, or TightVNC Viewer Linux…
Static linking embeds all library code directly into your binary. On Linux, this sounds straightforward but glibc introduces complications that pure static binaries don’t truly exist — the C library still loads dynamic features at runtime like NSS (Name Service Switch), locale data, and character set converters. Understanding these constraints is essential before committing to…
Vim’s default OCaml indentation is mediocre at best. The ocp-indent tool provides intelligent, syntax-aware indentation that respects OCaml conventions and integrates cleanly with Vim and Neovim. Installing ocp-indent Install via opam: opam install ocp-indent This installs the indentation engine and Vim plugin support. Verify the installation: which ocp-indent Configuring Vim Add this to your ~/.vimrc…
RAID0 (striping) on enterprise RAID controllers like Broadcom MegaRAID is used to expose multiple disks as a single logical volume with no redundancy. This configuration is appropriate only for performance-critical workloads where data loss from a single disk failure is acceptable, or for temporary/cache storage. This guide covers the full setup process on servers with…
Linux device names like /dev/sda and /dev/sdb are unreliable identifiers for physical hardware. They shift when you add, remove, or reseat drives, and there’s no guaranteed mapping between a SATA port and its device name. When a disk fails, you need to know exactly which physical slot to replace—guessing wrong takes down the wrong system….
mailx (heirloom-mailx) and s-nail are lightweight CLI tools for sending email from scripts, cron jobs, and system alerts. They’re especially useful in corporate or campus networks with internal SMTP servers that don’t require authentication. Installation Debian/Ubuntu: apt install heirloom-mailx RHEL/CentOS/Fedora: dnf install mailx Alpine: apk add mailx Arch: pacman -S s-nail s-nail is a modern…
NFSv3 uses multiple RPC services, each requiring its own port assignment. Without explicit configuration, rpcbind assigns random high ports to four critical services, making firewall rules unmaintainable. Modern deployments should prioritize NFSv4 with Kerberos, but legacy NFSv3 environments remain common enough to warrant proper port management. The NFS service stack includes seven RPC programs: Service…
SSH port forwarding lets you tunnel network traffic through an encrypted connection, making it essential for accessing services on restricted networks, exposing local services safely, or routing traffic through a jump host. This guide covers the three main types and production-ready practices. Local Forwarding Local forwarding listens on your local machine and relays connections through…
The proprietary fglrx driver reached end-of-life in 2015 and is incompatible with current Fedora releases. For modern AMD GPUs, use AMDGPU—AMD’s actively maintained open-source driver that supports Wayland, current kernel versions, and both desktop and compute workloads. GPU Compatibility RDNA and newer (RX 5000 series and later): AMDGPU is required and fully supported. GCN-era Radeons…
Xen remains in production use at scale across AWS EC2, Citrix Hypervisor, and various cloud providers, though KVM has become the default hypervisor for most Linux distributions. If you’re operating a Xen environment, Dom0 resource management is critical to system stability. Why Dom0 Resource Management Matters Dom0 performance directly affects your entire virtualized infrastructure. Since…
This guide sets up OpenLDAP for centralized authentication and NFS with automount to provide unified home directories across a cluster. The setup uses modern OpenLDAP backends and current NFS4 best practices. System Environment Server: LDAP and NFS: 10.0.0.2, Fedora 41 x86_64 Base DN: dc=lgcpu1 Clients: Range: 10.0.0.1/24, Fedora 41 x86_64 LDAP Server Setup Package Installation…
UDP (User Datagram Protocol) defined in RFC 768 provides a lightweight alternative to TCP. Unlike TCP’s stream-oriented approach, UDP delivers discrete packets — each recvfrom() or recvmsg() call returns one complete datagram. The tradeoff is real: you gain speed and lower overhead, but lose automatic reliability guarantees. Your application must handle packet loss, reordering, and…
Measuring time accurately matters for performance profiling, benchmarking, and latency-sensitive applications. Linux provides several APIs with different tradeoffs in resolution, overhead, and reliability. Understanding which to use prevents subtle bugs in production code. POSIX Time APIs: gettimeofday and clock_gettime gettimeofday() and clock_gettime() are the standard POSIX calls for reading system time. gettimeofday() returns seconds and…
When /etc/fstab contains errors or your hardware configuration changes, the system may fail to boot or hang during the mount phase. You can recover by modifying kernel parameters at boot time to bypass automatic mounting, then repair the configuration. Method 1: Boot to Single-User Mode Single-user mode skips mounting filesystems listed in fstab, letting you…
The passwd command is designed for interactive use—it prompts for input rather than accepting passwords via stdin by default. When you need to set passwords programmatically (bulk user provisioning, CI/CD automation, remote administration), you need methods that bypass the interactive prompt. Using passwd with –stdin The –stdin flag tells passwd to read the new password…
Ubuntu locks the root account by default as a safety measure—it prevents accidental system damage and enforces audit trails through sudo. If you genuinely need direct root access, here’s how to enable it and the security tradeoffs involved. Set a root password The simplest approach: sudo passwd root You’ll be prompted to enter and confirm…