diff --git a/nixos/modules/services/backup/postgresql-backup.nix b/nixos/modules/services/backup/postgresql-backup.nix
index f9f9568faa5..11efa47ec5b 100644
--- a/nixos/modules/services/backup/postgresql-backup.nix
+++ b/nixos/modules/services/backup/postgresql-backup.nix
@@ -6,11 +6,11 @@ let
 
   cfg = config.services.postgresqlBackup;
 
-  postgresqlBackupService = db :
+  postgresqlBackupService = db: dumpCmd:
     {
       enable = true;
 
-      description = "Backup of database ${db}";
+      description = "Backup of ${db} database(s)";
 
       requires = [ "postgresql.service" ];
 
@@ -26,7 +26,7 @@ let
           ${pkgs.coreutils}/bin/mv ${cfg.location}/${db}.sql.gz ${cfg.location}/${db}.prev.sql.gz
         fi
 
-        ${config.services.postgresql.package}/bin/pg_dump ${cfg.pgdumpOptions} ${db} | \
+        ${dumpCmd} | \
           ${pkgs.gzip}/bin/gzip -c > ${cfg.location}/${db}.sql.gz
       '';
 
@@ -42,9 +42,7 @@ let
 in {
 
   options = {
-
     services.postgresqlBackup = {
-
       enable = mkOption {
         default = false;
         description = ''
@@ -61,6 +59,19 @@ in {
         '';
       };
 
+      backupAll = mkOption {
+        default = cfg.databases == [];
+        defaultText = "services.postgresqlBackup.databases == []";
+        type = lib.types.bool;
+        description = ''
+          Backup all databases using pg_dumpall.
+          This option is mutual exclusive to
+          <literal>services.postgresqlBackup.databases</literal>.
+          The resulting backup dump will have the name all.sql.gz.
+          This option is the default if no databases are specified.
+        '';
+      };
+
       databases = mkOption {
         default = [];
         description = ''
@@ -79,18 +90,36 @@ in {
         type = types.string;
         default = "-Cbo";
         description = ''
-          Command line options for pg_dump.
+          Command line options for pg_dump. This options is not used
+          if <literal>config.services.postgresqlBackup.backupAll</literal> is enabled.
+          Note that config.services.postgresqlBackup.backupAll is also active,
+          when no databases where specified.
         '';
       };
     };
 
   };
 
-  config = mkIf config.services.postgresqlBackup.enable {
-
-    systemd.services = listToAttrs (map (db : {
+  config = mkMerge [
+    {
+      assertions = [{
+        assertion = cfg.backupAll -> cfg.databases == [];
+        message = "config.services.postgresqlBackup.backupAll cannot be used together with config.services.postgresqlBackup.databases";
+      }];
+    }
+    (mkIf (cfg.enable && cfg.backupAll) {
+      systemd.services.postgresqlBackup =
+        postgresqlBackupService "all" "${config.services.postgresql.package}/bin/pg_dumpall";
+    })
+    (mkIf (cfg.enable && !cfg.backupAll) {
+      systemd.services = listToAttrs (map (db:
+        let
+          cmd = "${config.services.postgresql.package}/bin/pg_dump ${cfg.pgdumpOptions} ${db}";
+        in {
           name = "postgresqlBackup-${db}";
-          value = postgresqlBackupService db; } ) cfg.databases);
-  };
+          value = postgresqlBackupService db cmd;
+        }) cfg.databases);
+    })
+  ];
 
 }
diff --git a/nixos/tests/postgresql.nix b/nixos/tests/postgresql.nix
index 1d434b62a5c..975ba7f488e 100644
--- a/nixos/tests/postgresql.nix
+++ b/nixos/tests/postgresql.nix
@@ -21,7 +21,7 @@ let
     CREATE TABLE xmltest ( doc xml );
     INSERT INTO xmltest (doc) VALUES ('<test>ok</test>'); -- check if libxml2 enabled
   '';
-  make-postgresql-test = postgresql-name: postgresql-package: makeTest {
+  make-postgresql-test = postgresql-name: postgresql-package: backup-all: makeTest {
     name = postgresql-name;
     meta = with pkgs.stdenv.lib.maintainers; {
       maintainers = [ zagy ];
@@ -29,14 +29,17 @@ let
 
     machine = {...}:
       {
-        services.postgresql.package=postgresql-package;
+        services.postgresql.package = postgresql-package;
         services.postgresql.enable = true;
 
         services.postgresqlBackup.enable = true;
-        services.postgresqlBackup.databases = [ "postgres" ];
+        services.postgresqlBackup.databases = optional (!backup-all) "postgres";
       };
 
-    testScript = ''
+    testScript = let
+      backupName = if backup-all then "all" else "postgres";
+      backupService = if backup-all then "postgresqlBackup" else "postgresqlBackup-postgres";
+    in ''
       sub check_count {
         my ($select, $nlines) = @_;
         return 'test $(sudo -u postgres psql postgres -tAc "' . $select . '"|wc -l) -eq ' . $nlines;
@@ -56,12 +59,20 @@ let
       $machine->succeed(check_count("SELECT xpath(\'/test/text()\', doc) FROM xmltest;", 1));
 
       # Check backup service
-      $machine->succeed("systemctl start postgresqlBackup-postgres.service");
-      $machine->succeed("zcat /var/backup/postgresql/postgres.sql.gz | grep '<test>ok</test>'");
-      $machine->succeed("stat -c '%a' /var/backup/postgresql/postgres.sql.gz | grep 600");
+      $machine->succeed("systemctl start ${backupService}.service");
+      $machine->succeed("zcat /var/backup/postgresql/${backupName}.sql.gz | grep '<test>ok</test>'");
+      $machine->succeed("stat -c '%a' /var/backup/postgresql/${backupName}.sql.gz | grep 600");
       $machine->shutdown;
     '';
 
   };
 in
-  mapAttrs' (p-name: p-package: {name=p-name; value=make-postgresql-test p-name p-package;}) postgresql-versions
+  (mapAttrs' (name: package: { inherit name; value=make-postgresql-test name package false;}) postgresql-versions) // (
+    # just pick one version for the dump all test
+    let
+      first = head (attrNames postgresql-versions);
+      name = "${first}-backup-all";
+    in {
+      ${name} = make-postgresql-test name postgresql-versions.${first} true;
+    }
+  )