Infrastructure
Why Your Server Is Slow #5: When the Database Slows Down — Indexes, Locks, Connection Pools
Tracking down why a database that ran fine is getting slower. Covers full scans collapsing the day data growth crosses a threshold, indexes that exist but never get used, lock wait chains rooted in long transactions, telling pool exhaustion from database saturation, and a diagnostic order built on EXPLAIN and the statistics views.
Migrating EC2 to Graviton — Real Savings and a Migration Checklist
What moving x86 instances to Graviton (arm64) actually saves, and the procedure for getting there: the generation landscape (Graviton4 mainstream, Graviton5 GA), which workloads move easily and where it gets stuck, multi-architecture image builds, canary cutover, and extending to RDS and Lambda.
Why Your Server Is Slow #4: Plenty of Bandwidth, Still Slow — Latency, RTT, Retransmissions
Tracking down why the network feels slow while the link sits mostly idle. Covers how RTT times round-trip count sets perceived speed, the handshake cost of TCP and TLS, BDP and window limits, checking packet loss and retransmissions, and connection reuse.
AWS Services and Settings That Quietly Leak Money — a Standing Checklist
The waste that raises your AWS baseline without ever making a spike: leftover gp2 volumes, public IPv4 addresses, NAT Gateway by design, logs retained forever, old instance generations, abandoned load balancers, S3 storage classes, and dev environments running around the clock — with how to check each one.
Why Your Server Is Slow #3: Slow Despite an SSD — Write Amplification, fsync, Queue Depth
Tracking down why storage is the bottleneck even on an SSD. Covers the fine print behind spec-sheet IOPS, the cost of durable writes through fsync, SLC cache exhaustion and write amplification, the physical limits of queue depth 1, and the IOPS ceilings of cloud volumes.
When Your AWS Bill Suddenly Jumps — the 10 Most Common Causes
A field guide for the month your AWS bill doubles: the order for finding the culprit, and the ten causes that come up most in practice — NAT Gateway data processing, CloudWatch Logs ingestion, snapshot accumulation, data transfer, expiring RIs and Savings Plans — each with how to confirm it and what to do.
Why Your Server Is Slow #2: More Memory Didn't Help — Page Cache, Swap, Working Set
Tracking down why adding memory left performance unchanged. Covers what available really means, how spare memory already works as page cache, judging swap by movement rather than usage, sizing the working set, and the container limits and application heaps that upgrades never reach.
Why Your Server Is Slow #1: Low CPU Usage but Still Slow — Run Queue, I/O Wait, Lock Contention
Tracking down why a server is slow while CPU usage stays low. Covers run queue and scheduling delay, the iowait trap, lock contention and off-CPU waits, and steal time in the cloud — a diagnostic order for finding the waiting that utilization graphs miss.
Hardware Advanced #7: Firmware, BMC, and the Lifecycle — The Other Computer Inside Your Server
A look at the BMC, the management computer that stays on independently of the main CPU. It covers remote console and power control, IPMI and Redfish, the firmware stack and update operations, failure prediction with SMART and ECC counters, management-network security, and the lifecycle from warranty expiry to disk disposal — closing out the Hardware Advanced series.
Hardware Advanced #6: Data Center Cooling and Racks — Electricity Always Becomes Heat
Nearly all the power that enters a server comes back out as heat. Starting from the basic airflow contract of front intake and rear exhaust, this post maps out data center cooling end to end: hot/cold aisle containment, rack density and the limits of air cooling, liquid cooling with D2C and immersion, and how ASHRAE temperature guidelines tie into PUE.
Hardware Advanced #5: Datacenter Power — The Real Reason You Can't Rack More Servers
Even with empty slots in the rack, new servers get rejected — because of the power budget. This post walks the power environment a server lives in, from an operator's point of view: PSU redundancy and A/B feeds, per-rack kW contracts, PDUs and UPS, generators and ATS, PUE, and the power density that GPU servers have driven up.
Hardware Advanced #4: ZFS Deep Dive — When RAID and the Filesystem Become One
ZFS merged RAID, volume management, and the filesystem into a single layer, solving the structural problems of the traditional stack. This post walks through it all from an operations point of view: copy-on-write that eliminates the write hole, checksums that verify every read with self-healing, resilver that copies only live data, RAIDZ and the ARC, snapshots with send/recv, and lz4 compression.