# nixbuild.net's First Year: Stability Improvements and Build Result Reuse

DevFeed: [nixbuild.net's First Year: Stability Improvements and Build Result Reuse](<https://devfeed.tech/articles/the-first-year-34134.md>)

Original publisher: [Read original article](<https://blog.nixbuild.net/posts/2020-12-29-the-first-year.html>)

Author: support@nixbuild.net

Published: 2020-12-29T00:00:00Z

Content type: article

Language: en

Sources: [nixbuild.net blog](<https://devfeed.tech/sources/nixbuild-net-blog.md>)

Topics: [Nix](<https://devfeed.tech/topics/nix.md>), [builds](<https://devfeed.tech/topics/builds.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Filesystems](<https://devfeed.tech/topics/filesystems.md>)

## AI overview

The article reviews nixbuild.net's first year, describing stability and performance improvements after general availability and new ways to reuse build results, including certain previously failed builds.

## Source excerpt

One year ago nixbuild.net was announced to the Nix community for the very first time. The service then ran as a closed beta for 7 months until it was made generally available on the 28th of August 2020. This blog post will try to summarize how nixbuild.net has evolved since GA four months ago, and give a glimpse of the future for the service. Stability and Performance Thousands of Nix builds have been built by nixbuild.net so far, and every build helps in making the service more reliable by uncovering possible edge cases in the build environment. These are some of the stability-related improvements and fixes that have been deployed since GA: Better detection and handling of builds that time out or hang. Improved retry logic should our backend storage not deliver Nix closures as expected. Fixes to the virtual file system inside the KVM sandbox. Better handling of builds that have binary data in their log output. Changes to the virtual sandbox environment so it looks even more like a "standard" Linux environment. Application of the Nix sandbox inside our KVM sandbox. This basically guarantees that the Nix environment provided through nixbuild.net is identical to the Nix environment for local builds. Support for following HTTP redirects from binary caches. Even Better Build Reuse One of the fundamental ideas in nixbuild.net is to try as hard as possible to not build your builds, if an existing build result can be reused instead. We can trivially reuse an account's own builds since they are implicitly trusted by the user, but also untrusted builds can be reused under certain circumstances. This has been described in detail in an earlier blog post Since GA we've introduced a number of new ways build results can be reused. Reuse of Build Failures Build failures are now also reused. This means that if someone tries to build a build that is identical (in the sense that the derivation and its transitive input closure is bit-by-bit identical) to a previously failed build, nix