Downloads and copies to the nix store and some other opertaions on macOS are suddenly very slow

Hi folks!

I’m trying to debug an issue on macOS (Intel, Sonoma) where downloading files and copying them to the nix store can be come incredibly slow - hazarding a guess it’s maybe 100Kbps. However, when pulling the same file from firefox, the connection at the same time as nix attempting to download the file is about 2Mbps or higher.

Example download file was: nixpkgs-b5b4f5a1006da4f5a9c3637ade7c0baa1ea6677a.tar.gz

Not entirely sure this is related, but using cachix devenv, the command devenv init is also taking an incredibly long time in a blank directory - this happened about the same time as I noticed the downloads running quite slow.

I’ve completely reinstalled macOS after wiping the partition, for a little while everything seemed resolved, but I am starting to see these issues again with minimal installations.

Is there some area I can begin to debug? I’m a little at a loss here. Nothing has shown up in wireshark that is out of the ordinary.

Just to bump this and rule out something simple: how much storage space do you have free?

This does remind me of something I’ve seen discussion around, but I can’t readily recall where and some casual searching here and on github hasn’t turned up anything that smells like a match, yet.

Thanks abathur.

Storage before the wipe was at least 100GB free. After the wipe was close to 450GB. The issue was still presenting for a while after wiping and reinstalling macOS, then nix. I also checked SMART and any other drive diagnostics I could think of, everything was fine and no other software was showing similar behavior.

A few hours after I made this post, of course things seem to have resolved themselves. Maybe there is a particular package that is just slow for pulling via nix. I’ll keep monitoring.

Thanks for reminding me of this post. I’m ok with closing it but hate to do so without knowing a bit more around what could cause this for anyone looking in the future.

1 Like