--- title: "Stop writing caches that no later run restores" description: "Remove cache writes and archives that have no consumer, eliminating work without changing the build result." url: https://starsling.dev/ci-playbooks/techniques/disable-unused-caches canonicalUrl: https://starsling.dev/ci-playbooks/techniques/disable-unused-caches --- # Stop writing caches that no later run restores Remove cache writes and archives that have no consumer, eliminating work without changing the build result. ## How to choose an approach This technique currently has one documented company example. Validate its prerequisites, tradeoffs and original CI environment against your repository before adapting it. - **[DoorDash](https://starsling.dev/ci-playbooks/doordash#drop-unrestored-build-cache)**: Use it when A build tool writes a large local cache on every CI run, and no cache step saves or restores that directory. Check before adopting: Keep the cache wherever a later run restores it (developer machines, or CI with a cache step whose hit rate you have measured). ## Apply this technique ````text Evaluate and apply this CI technique to my repository: Stop writing caches that no later run restores. Remove cache writes and archives that have no consumer, eliminating work without changing the build result. Read the technique and its source-backed company examples: https://starsling.dev/ci-playbooks/techniques/disable-unused-caches.md Inspect this repository’s CI workflows, build and test commands, dependencies, and recent run timings. Identify where this technique applies and explain the expected benefit using this repository’s evidence. Measure a baseline from recent comparable runs: elapsed time, queue time, runner minutes and failures where available. If data is unavailable, say what cannot be measured. Compare relevant company approaches, checking prerequisites, platform differences and tradeoffs. Rank applicable options by evidence, fit and measurable opportunity; do not present company results as predictions for this repo. Recommend the smallest safe change, show what checks and fallback paths remain, and ASK ME WHICH CHANGE TO APPROVE BEFORE EDITING ANY FILES. Only after approval, work on a new feature branch, make one reversible change, and open a reviewable pull request. Never merge or push to a default or protected branch. Keep required checks, test coverage, deployment and release behavior intact. Validate the change and compare equivalent runs where possible; report limitations and what should be monitored after merge. ```` ## How DoorDash used this technique Read what DoorDash changed and follow the original sources. ### DoorDash: Turn off a build cache that CI never restores Next.js caches Webpack, ESLint and SWC under .next/cache by default, and for large projects the Webpack cache can exceed 5 to 10 GB. CI jobs never saved that cache between runs, so every write was wasted disk activity. Disabling the Webpack disk cache in CI saved three minutes per run. Evidence: Documented technique Use it when: A build tool writes a large local cache on every CI run, and no cache step saves or restores that directory. Before applying it: Keep the cache wherever a later run restores it (developer machines, or CI with a cache step whose hit rate you have measured). [Read more in the DoorDash playbook](https://starsling.dev/ci-playbooks/doordash#drop-unrestored-build-cache) [Primary source](https://careersatdoordash.com/blog/how-doordash-slashed-web-developer-build-times/) ## CI optimization is continuous work. Apply this technique yourself, or use StarSling Runners for faster GitHub Actions and optional agent-driven optimization PRs, which teams on eligible paid plans can turn on. [Get self-improving CI](https://starsling.dev/products/runners) ## Related techniques ### [Reduce the setup floor before increasing shard count](https://starsling.dev/ci-playbooks/techniques/setup-cost-limits-sharding) Each extra shard repeats checkout, dependencies and container setup. 1 implementation · 1 company (Linear) ### [Remove caches that cost more than they save](https://starsling.dev/ci-playbooks/techniques/remove-expensive-caches) Measure cache restore and upload time against the work avoided. Remove caches whose transfer cost outweighs their benefit. 2 implementations · 2 companies (Linear, OpenAI) ### [Bake stable dependencies into runner images](https://starsling.dev/ci-playbooks/techniques/prebuild-runner-images) Prepare versioned system dependencies and build downloads once in the runner image instead of installing them on every job. 2 implementations · 2 companies (Anthropic, Linear) ## Company Playbooks ### [Anthropic](https://starsling.dev/ci-playbooks/anthropic) Run only affected tests ### [DoorDash](https://starsling.dev/ci-playbooks/doordash) Run build and test in parallel, sharded across CI agents ### [Linear](https://starsling.dev/ci-playbooks/linear) Benchmark the same job on faster hardware ### [Mastra](https://starsling.dev/ci-playbooks/mastra) StarSling runners for the slowest test workflow ### [OpenAI](https://starsling.dev/ci-playbooks/openai) Rank CI fixes by the minutes they save ### [Ramp](https://starsling.dev/ci-playbooks/ramp) Move a CPU-bound test suite to a faster CPU ### [Shopify](https://starsling.dev/ci-playbooks/shopify) Let an agent iterate against one CI metric ### [Spotify](https://starsling.dev/ci-playbooks/spotify) Build arm64 on native arm64 runners ### [Stripe](https://starsling.dev/ci-playbooks/stripe) Run only the tests a change can reach ### [Uber](https://starsling.dev/ci-playbooks/uber) Build the merge-queue speculations most likely to be needed ## Related guides Implementation guides for this technique. ### [Cache workflow dependencies](https://starsling.dev/best-practices/github-actions/cache-dependencies) Choose dependency cache paths and keys for your package manager. ### [Cut repeated test setup](https://starsling.dev/best-practices/github-actions/cut-repeated-test-setup) Share expensive setup at the scope your tests need. ### [Share setup steps across jobs](https://starsling.dev/github-actions/optimizations/avoid-duplicated-setup) Centralize repeated setup definitions and remove duplicate or unused steps. ### [Optimize npm installs](https://starsling.dev/github-actions/optimizations/optimize-npm-install) Cache npm dependencies and large downloads and remove unused tool installs. ### [Optimize pnpm installs](https://starsling.dev/github-actions/optimizations/optimize-pnpm-install) Set up the pnpm store cache in the right order and scope recursive commands. ### [Bound runner jobs with timeouts](https://starsling.dev/best-practices/github-actions/bound-job-timeouts) Set job and step timeouts using expected durations and failure behavior.