A deep dive into the 'stat storm' problem in Nix, where the dynamic loader makes hundreds of failing openat() syscalls before a program even starts. The root cause is Nix's per-package store layout requiring long DT_RUNPATH lists in ELF headers, causing O(N×M) failed library searches. Five approaches are analyzed: absolute DT_NEEDED paths (fast but breaks LD_LIBRARY_PATH overrides), RUNPATH symlink farms (preserves overrides but can't handle duplicate sonames), per-DSO ELF note caches (best tradeoffs but requires glibc patch), Guix-style per-package ld.so.cache (breaks cross-compilation), and static linking with musl (drops devenv from 70ms to 16ms but not a general fix). The chosen solution is the ELF note cache, now shipped in patchelf 0.19.0, with a nixpkgs PR pending to enable it across the whole package set. The goal is eventually upstreaming the glibc loader patch.
