Add additional build target which optimizes for size #1347

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MrUnknownDE · 2026-04-06T01:48:40+02:00

MrUnknownDE commented

2026-04-06 01:48:40 +02:00

Originally created by @gladiac on 11/23/2023

OpenWRT (https://openwrt.org) is a project which builds and distributes firmware for embedded devies like routers, access points, and so on. These devices are usually very limited in terms of storage. Therefore, optimizing binaries for size at the cost of execution speed is usually desired. As I intend to provide a vaultwarden package for OpenWRT this change would help significantly.

This PR adds an additional build-target, namely "release-micro", which implements several parameters which optimize in favor of binary size.

The following parameters were chosen:

opt-level "z": Optimize for size with disabled loop vectorization
strip "symbols": Strip debuginfo and symbols from binary
lto "fat": Enable link-time optimizations across all crates
codegen-units 1: Disable parallelization of code generation to allow for additional optimizations
panic "abort": Abort on Panic() instead of unwinding

All these build parameters significantly reduce the binary size from >40MB to <15MB - the actual amount depends on the target architecture.

I would like to upstream this new build target to keep our build environment simple. Other projects which deploy vaultwarden on size-constrained environments may benefit from this change too.

*Originally created by @gladiac on 11/23/2023* OpenWRT (https://openwrt.org) is a project which builds and distributes firmware for embedded devies like routers, access points, and so on. These devices are usually very limited in terms of storage. Therefore, **optimizing binaries for size** at the cost of execution speed is usually desired. As I intend to provide a vaultwarden package for OpenWRT this change would help significantly. This PR adds an additional build-target, namely "release-micro", which implements several parameters which optimize in favor of binary size. The following parameters were chosen: - opt-level "z": Optimize for size with disabled loop vectorization - strip "symbols": Strip debuginfo and symbols from binary - lto "fat": Enable link-time optimizations across all crates - codegen-units 1: Disable parallelization of code generation to allow for additional optimizations - panic "abort": Abort on Panic() instead of unwinding All these build parameters significantly reduce the binary size from >40MB to <15MB - the actual amount depends on the target architecture. I would like to upstream this new build target to keep our build environment simple. Other projects which deploy vaultwarden on size-constrained environments may benefit from this change too.

MrUnknownDE closed this issue

2026-04-06 01:48:40 +02:00

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Reference: github/vaultwarden#1347