SysAdmin

A quick MySQL command to check the peak number of simultaneous connections your server has handled, useful for capacity planning and diagnosing connection bottlenecks.

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.

A practical breakdown of how Linux file permissions work, including the symbolic and numeric chmod methods, special bits like setuid and sticky, and how permissions differ between files and directories.

A practical guide to reading Linux load averages, with a traffic analogy that makes the numbers click. Learn the thresholds that matter, how multi-core systems change the math, and which of the three averages to watch.