Switch cache.nixos.org to ZSTD to fix slow NixOS updates / nix downloads?

Development
55

I haven’t seen XZ decompression be a bottleneck on any system.

My opening post shows exactly that 100x bottleneck:

despite only pushing ~12 MB/s, the nix process consumes around 100% CPU (varying between 70% and 130% in htop).

If additionally the network pipe is now slow, that’s also bad and should be fixed, but it doesn’t make the already-proven issue disappear.

In my test today on 10 Gbit/s,

wget -O /dev/null https://cache.nixos.org/nar/1w0nk8lhf3vbna1cl07qs835f13xj7w60mx7ny3xx3rxk6waxk1r.nar.xz

runs at 5 MB/s. That’s faster than 1 MB/s but still atrocious.

1 Like