SysAdmin

A follow-up to the original MySQL NUMA swap post, explaining why the real issue is memory pressure on a single NUMA node rather than swap itself, and outlining a three-part solution for balanced allocation in production.

A quick reference for the process state codes shown in the STAT column of ps aux, including both standard and BSD-specific flags.

A quick reference for the core RCS (Revision Control System) commands used to initialize, check in, check out, and log file revisions on a Linux system.

Slow Loris attacks tie up web server sockets with trickling requests until legitimate traffic is starved. This post walks through configuring Apache mod_qos to detect and block those connections automatically.

A quick procedure to verify and correct a time mismatch between the host system clock and MySQL’s internal NOW() function, using a simple service restart.

A quick reference for GNU find -printf format switches, with practical examples for inspecting file ownership, size, and mode. Includes a use case for auditing files recovered into lost+found after a filesystem check.