hosts/epyc.nix

@@ -1,15 +1,9 @@
-{ lib, ... }:
-let
-  gcc-system-features = arch: lib.optionals (arch != null) ([ "gccarch-${arch}" ]
-    ++ map (x: "gccarch-${x}") lib.systems.architectures.inferiors.${arch});
-in
 {
   imports = [
     ../modules/ipmi-supermicro.nix
     ../modules/hardware/supermicro-H12SSL-i.nix
     ../modules/iperf-server.nix
     ../modules/hypervisor.nix
-    ../modules/hydra/coordinator.nix
   ];
 
   networking.hostName = "epyc";
@@ -24,18 +18,7 @@ in
     };
   };
 
-  nix.buildMachines = [
-    { hostName = "localhost";
-      systems = [
-        "x86_64-linux"
-        "riscv64-linux"
-      ];
-      supportedFeatures = [ "kvm" "nixos-test" "big-parallel" "benchmark" ] ++ gcc-system-features "znver3";
-      maxJobs = 1;
-    }
-  ];
-
-  boot.binfmt.emulatedSystems = [ "riscv64-linux" "aarch64-linux" "riscv64-linux" ];
+  boot.binfmt.emulatedSystems = [ "aarch64-linux" "riscv64-linux" ];
 
   simd.arch = "znver3";
   system.stateVersion = "23.05";

modules/hydra/coordinator.nix

@@ -1,81 +0,0 @@
-{ pkgs, ... }: {
-  services.hydra = {
-    enable = true;
-    hydraURL = "https://hydra.newtype.fr";
-    notificationSender = "hydra@localhost";
-    buildMachinesFiles = [ "/etc/nix/machines" ];
-    useSubstitutes = true;
-  };
-
-  environment.systemPackages = [ pkgs.nix-prefetch-git ];
-  nix.trustedUsers = [ "hydra" "hydra-www" ];
-
-  services.postgresql = {
-    enableJIT = true;
-    settings = {
-      checkpoint_completion_target = "0.9";
-      default_statistics_target = 100;
-
-      max_connections = 500;
-      work_mem = "20MB";
-      maintenance_work_mem = "2GB";
-
-      shared_buffers = "8GB";
-
-      min_wal_size = "1GB";
-      max_wal_size = "2GB";
-      wal_buffers = "16MB";
-
-      max_worker_processes = 16;
-      max_parallel_workers_per_gather = 8;
-      max_parallel_workers = 16;
-
-      # NVMe related performance tuning
-      effective_io_concurrency = 200;
-      random_page_cost = "1.1";
-
-      # We can risk losing some transactions.
-      synchronous_commit = "off";
-
-      effective_cache_size = "16GB";
-
-      # autovacuum and autoanalyze much more frequently:
-      # at these values vacuum should run approximately
-      # every 2 mass rebuilds, or a couple times a day
-      # on the builds table. Some of those queries really
-      # benefit from frequent vacuums, so this should
-      # help. In particular, I'm thinking the jobsets
-      # pages.
-      autovacuum_vacuum_scale_factor = 0.002;
-      autovacuum_analyze_scale_factor = 0.001;
-
-      shared_preload_libraries = "pg_stat_statements";
-      compute_query_id = "on";
-    };
-  };
-
-  security.acme = {
-    acceptTerms = true;
-    defaults.email = "ryan@lahfa.xyz";
-  };
-
-  services.nginx = {
-    enable = true;
-
-    recommendedZstdSettings = true;
-    recommendedBrotliSettings = true;
-    recommendedGzipSettings = true;
-    recommendedOptimisation =true;
-    recommendedTlsSettings = true;
-    recommendedProxySettings = true;
-  };
-
-  services.nginx.virtualHosts."hydra.newtype.fr" = {
-    forceSSL = true;
-    enableACME = true;
-    # TODO: remove compression for some locations
-    locations."/".proxyPass = "http://localhost:3000";
-  };
-
-  networking.firewall.allowedTCPPorts = [ 80 443 ];
-}

modules/nix-daemon.nix

@@ -42,17 +42,13 @@ in
       package = pkgs.nixVersions.nix_2_13;
 
       # should be enough?
-      nrBuildUsers = 128;
+      nrBuildUsers = lib.mkDefault 32;
 
       # https://github.com/NixOS/nix/issues/719
-      daemonCPUSchedPolicy = "batch";
-      daemonIOSchedClass = "best-effort";
-      daemonIOSchedPriority = 5;
 
       settings = {
         keep-outputs = true;
         keep-derivations = true;
-        max-jobs = 64;
         # in zfs we trust
         fsync-metadata = lib.boolToString (!config.boot.isContainer or config.fileSystems."/".fsType != "zfs");
         substituters = [