SysAdmin

A minimal Java class and JAAS configuration for testing Kerberos authentication in isolation, useful when application-level debugging is too noisy to isolate the problem.

An overview of graph databases, their structure, and advantages over relational models. Covers how nodes, relationships, and the Cypher query language work together to model complex data.

A walkthrough of using udevadm to diagnose and inspect udev rule application on a /dev/null device node. Covers the test command syntax and interprets the output for troubleshooting permission issues.

Tune Postgres per-table autovacuum settings and track them with a single SQL view. Covers global defaults, table-specific overrides, and a ready-to-use monitoring query.

A deep dive into how the Linux kernel receives network packets, covering the full path from NIC hardware through NAPI, softirqs, GRO, RPS, and protocol layers. Includes practical monitoring commands and tuning knobs for each stage.

A practical walkthrough of how Linux allocates and manages RX/TX ring buffers for network interfaces, covering DMA, softirq processing, and tuning knobs like netdev_budget.