iddqd, or the hardest kind of unsafe Rust

Tue, 02 Jun 2026 00:00:00 +0000

Mirrored from the canonical version on the Oxide blog.

I’m the main author of iddqd, a Rust library for maps (named after the Doom cheat code) where keys are borrowed from values. At Oxide we use it extensively in Omicron, our control plane—the software that sits at the heart of every Oxide rack, provisions resources like compute and storage for our customers, and ensures the rack stays up and running over time. iddqd maintains in-memory indexes of the kinds of large records that show up everywhere in a system like that, such as disks or sled inventories. As a result, it must be correct: if it misbehaves, our control plane can malfunction in ways that are unpredictable and hard to diagnose.

Unsafe on sunshowers

iddqd, or the hardest kind of unsafe Rust