diff --git a/nixos/modules/services/misc/gitlab.nix b/nixos/modules/services/misc/gitlab.nix
index 25c258ebe13..b8617e48d8e 100644
--- a/nixos/modules/services/misc/gitlab.nix
+++ b/nixos/modules/services/misc/gitlab.nix
@@ -22,7 +22,8 @@ let
       password = cfg.databasePassword;
       username = cfg.databaseUsername;
       encoding = "utf8";
-    };
+      pool = cfg.databasePool;
+    } // cfg.extraDatabaseConfig;
   };
 
   gitalyToml = pkgs.writeText "gitaly.toml" ''
@@ -253,6 +254,18 @@ in {
         description = "Gitlab database user.";
       };
 
+      databasePool = mkOption {
+        type = types.int;
+        default = 5;
+        description = "Database connection pool size.";
+      };
+
+      extraDatabaseConfig = mkOption {
+        type = types.attrs;
+        default = {};
+        description = "Extra configuration in config/database.yml.";
+      };
+
       host = mkOption {
         type = types.str;
         default = config.networking.hostName;