[Nix-dev] garbage collection and nix-push

[Mathijs Kwik]

Hi all,

The hardware I use for building my channel is not very powerful. It
does a good job of building derivations, but packing nar files with xz
takes ages.

My channel is nothing special, It just builds the configurations for a
few home machines and laptops and some packages that hydra doesn't
build with the optional dependencies I like.

By registering the outputs as gc roots, I made sure no extensive
rebuilds are performed when I don't change much.
However, after a garbage collector run, all nar outputs get removed,
leading to long push times on the next run.

So for now, I just lowered the garbage-collection cronjob to once a week.

Does anyone have a suggestion on how to work around this?
For example registering the nar outputs as (temp/indirect) gc roots or
steering the garbage collector not to remove outputs that were built
less than 48 hours ago or something?

Thanks,
Mathijs