Practical guides for system administrators — Windows, PowerShell, Active Directory, networking, and infrastructure.
When a datastore loses its backend storage connection, vCenter can keep it registered in its inventory even though the underlying volume is no longer accessible. The GUI unmount task fails with a “datastore in use” error, and the ESXi host…
This page is a structured reference for the most commonly used VMware PowerCLI cmdlets, organized by task area. Each entry includes the cmdlet name, its purpose, and a practical usage example. Use it as a quick lookup during scripting or…
Running individual PowerCLI commands interactively is useful for quick checks, but the real value of PowerCLI is in automation: scripts that run on a schedule, generate reports, or apply changes across dozens of VMs without manual intervention. This guide covers…
vSphere snapshots capture the state of a virtual machine at a specific point in time. They are useful before applying patches, running upgrades, or making configuration changes that may need to be rolled back. Managing snapshots manually through the vSphere…
OpenSSL is the standard command-line toolkit for working with certificates, keys, and SSL As a system administrator, you will use it to generate private keys, createcertificate signing requests, issue self-signed certificates, and convert between certificateformats. This guide covers the full…
Complete IPv4 and IPv6 subnetting reference. Subnet masks, CIDR notation, binary breakdown, private ranges, VLSM examples, and key formulas.
Introduction The error “The trust relationship between this workstation and the primary domain failed” is one of the most common issues administrators encounter in Active Directory environments. It usually appears when a domain-joined computer attempts to authenticate with a domain…
This reference covers the most useful Run dialog commands, Control Panel applets, management consoles, shell shortcuts, keyboard combinations, and PowerShell one-liners for Windows system administration. All commands work from Win + R, Command Prompt, or PowerShell unless noted otherwise. System…
Introduction If you’ve ever had to pull hardware specs, uninstall stubborn software, or automate system audits in Windows, chances are you’ve encountered either WMIC or PowerShell. These two tools have served as the go-to command-line utilities for Windows administrators and…
You boot up your computer and—bam!—Windows starts checking a drive for errors. Great… unless you’re in a rush and suddenly watching a countdown timer like it’s Y2K. Want to take control of those automatic disk checks? Meet your new friend:…
