adding root_pool/nix_build to all zfs boxes

this fixes issues with file how the test intract with zfs file systems

systems/bob/hardware.nix

@@ -50,8 +50,8 @@
       fsType = "zfs";
     };
 
-    "/nix_build" = {
-      device = "root_pool/nix_build";
+    "/nix/var/nix/builds" = {
+      device = "root_pool/nix/var/nix/builds";
       fsType = "zfs";
     };
 

systems/brain/hardware.nix

@@ -53,8 +53,8 @@
       fsType = "zfs";
     };
 
-    "/nix_build" = {
-      device = "root_pool/nix_build";
+    "/nix/var/nix/builds" = {
+      device = "root_pool/nix/var/nix/builds";
       fsType = "zfs";
     };
 

systems/jeeves/default.nix

@@ -24,10 +24,6 @@ in
     ./runners
     ./syncthing.nix
   ];
-  nix.settings.system-features = lib.mkAfter [
-    "gccarch-x86-64-v2"
-    "gccarch-x86-64-v3"
-  ];
 
   services = {
     openssh.ports = [ 629 ];

systems/jeeves/hardware.nix

@@ -96,8 +96,8 @@ in
       fsType = "zfs";
     };
 
-    "/nix_build" = {
-      device = "root_pool/nix_build";
+    "/nix/var/nix/builds" = {
+      device = "root_pool/nix/var/nix/builds";
       fsType = "zfs";
     };
 

systems/rhapsody-in-green/hardware.nix

@@ -40,8 +40,8 @@
       fsType = "zfs";
     };
 
-    "/nix_build" = {
-      device = "root_pool/nix_build";
+    "/nix/var/nix/builds" = {
+      device = "root_pool/nix/var/nix/builds";
       fsType = "zfs";
     };