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Raymond Ops

Linux ops automation, cloud-native, Kubernetes, SRE, DevOps, Python, Golang and related tech discussions.

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Latest from Raymond Ops

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Raymond Ops

Aug 4, 2026 · Information Security

A Miswritten iptables Rule That Almost Made Me Quit

The article recounts a real‑world iptables misconfiguration that cut off SSH access for 47 minutes, walks through the incident timeline, root‑cause analysis, and detailed remediation steps, and then expands into a comprehensive guide on iptables fundamentals, common pitfalls, best‑practice design, troubleshooting commands, automation, monitoring, and migration to nftables.

Incident Responseautomationfirewall

0 likes · 71 min read

A Miswritten iptables Rule That Almost Made Me Quit

Raymond Ops

Aug 3, 2026 · Databases

How to Diagnose MySQL Slow Queries Without Relying on Blind Indexing

This guide walks through a systematic approach to uncovering and fixing MySQL slow queries, covering slow‑query‑log configuration, log analysis with mysqldumpslow and pt‑query‑digest, EXPLAIN‑based execution‑plan inspection, index design principles, SQL rewrites, configuration tuning, and ongoing monitoring to prevent performance regressions.

Database ConfigurationEXPLAINIndex Optimization

0 likes · 27 min read

How to Diagnose MySQL Slow Queries Without Relying on Blind Indexing

Raymond Ops

Aug 2, 2026 · Artificial Intelligence

Why Your RAG Falls Short and How to Fix It: Common Pitfalls and Proven Optimizations

This article dissects why Retrieval‑Augmented Generation pipelines often underperform, examines root causes such as embedding model choice, chunking strategy, hybrid retrieval, and reranking, and provides concrete code samples, evaluation metrics, and step‑by‑step troubleshooting to dramatically improve results.

ChunkingEmbeddingRAG

0 likes · 18 min read

Why Your RAG Falls Short and How to Fix It: Common Pitfalls and Proven Optimizations

Raymond Ops

Aug 1, 2026 · Databases

Essential MySQL Backup and Recovery Process Every Ops Engineer Must Master

This comprehensive guide walks MySQL administrators through the fundamentals of backup and recovery, covering RPO/RTO concepts, tool comparisons (mysqldump, mydumper, xtrabackup), step‑by‑step scripts for full, incremental, and binlog backups, encryption, compression, troubleshooting, and best‑practice monitoring to ensure data safety and rapid restoration.

BackupDatabase OperationsMySQL

0 likes · 35 min read

Essential MySQL Backup and Recovery Process Every Ops Engineer Must Master

Raymond Ops

Aug 1, 2026 · Operations

Linux Triple Threat: Practical grep, sed, and awk Tips to Double Your Efficiency

This guide explains why the three classic Unix tools—grep, sed, and awk—are indispensable for sysadmins, compares their strengths, shows real‑world examples for log analysis, configuration management, and large‑file processing, and provides performance‑tuned techniques that can cut task times from minutes to seconds.

Shell Scriptingawkgrep

0 likes · 48 min read

Linux Triple Threat: Practical grep, sed, and awk Tips to Double Your Efficiency

Raymond Ops

Jul 31, 2026 · Operations

Which Nginx Parameters Should You Tune First for High‑Concurrency Scenarios?

This guide explains how to boost Nginx performance under thousands of QPS by adjusting OS kernel limits, worker process settings, buffer sizes, upstream keep‑alive, HTTP/2, gzip, caching, load‑balancing strategies, and provides a step‑by‑step validation checklist.

GZIPNginxcaching

0 likes · 26 min read

Which Nginx Parameters Should You Tune First for High‑Concurrency Scenarios?

Raymond Ops

Jul 28, 2026 · Databases

MySQL Disk Space Explodes: How Binary Logs Become the Hidden Culprit

MySQL servers can trigger alarming disk‑space warnings even when the data directory is small, because unchecked binary logs rapidly consume storage; this article explains the log’s purpose, why it grows, how to diagnose the issue, and provides step‑by‑step cleanup, configuration, replication, monitoring, and recovery best practices.

BackupBinary LogDisk Space

0 likes · 26 min read

MySQL Disk Space Explodes: How Binary Logs Become the Hidden Culprit

Raymond Ops

Jul 27, 2026 · Databases

What to Do First When MySQL Connections Are Maxed Out

This guide walks you through a complete emergency response, root‑cause analysis, and long‑term mitigation for MySQL connection‑limit exhaustion, covering Linux diagnostics, SQL commands, quick‑kill scripts, monitoring with Prometheus/Grafana, and best‑practice configuration of connection pools and max_connections.

MySQLconnection limitsmonitoring

0 likes · 37 min read

What to Do First When MySQL Connections Are Maxed Out

Raymond Ops

Jul 27, 2026 · Information Security

Why Sharing a Root Account in Production Is a Dangerous Mistake

Sharing a single root account on production servers creates severe security risks, prevents reliable auditing and fault isolation, and leads to accountability problems, as demonstrated by real incidents; the article explains these issues in detail and recommends personal accounts with sudo, audit logging, and bastion‑host solutions.

Linux securityauditdbastion host

0 likes · 36 min read

Why Sharing a Root Account in Production Is a Dangerous Mistake

Raymond Ops

Jul 26, 2026 · Information Security

How to Prevent Linux Privilege Escalation? Critical Risks Every Junior Ops Should Know

This article explains the most common Linux privilege‑escalation vectors—including unsafe SUID binaries, mis‑configured sudo, vulnerable cron jobs, password and SSH‑key leaks, kernel and software bugs, container escape, and file‑permission flaws—and provides concrete hardening steps and a quick‑check script for ops engineers.

CronSUIDcontainer escape

0 likes · 24 min read

How to Prevent Linux Privilege Escalation? Critical Risks Every Junior Ops Should Know