Why every durable store writes the log first.
This is one of the longer-form guides in the Toolkit. The original write-up — including diagrams, sequence traces, and the code samples — will migrate here verbatim, restyled for the new editorial layout. What follows is a short preview of the ground the piece covers.
What the piece covers
The guide walks through write-ahead logging from the surface down. It starts with the interface you already know, then pulls back each layer until you can see how the machine actually does its work. Along the way it names the failure modes that are interesting, and the ones that are not worth worrying about.
How it pairs with the tools
Every guide cross-references at least one tool or simulator in the Toolkit — because the fastest way to learn something mechanical is to push on it. The 9 min estimate assumes a read-through; add time if you stop to play.
What you'll take away
A mental model you can draw on a whiteboard, a short list of failure modes to watch for in production, and a few sharp definitions that make the next conversation about this topic much easier.