diff --git a/nixos/modules/rename.nix b/nixos/modules/rename.nix
index 8393b5758f3c..f41bababd293 100644
--- a/nixos/modules/rename.nix
+++ b/nixos/modules/rename.nix
@@ -124,6 +124,8 @@ in zipModules ([]
 ++ obsolete [ "services" "mesa" "s3tcSupport" ] [ "hardware" "opengl" "s3tcSupport" ]
 ++ obsolete [ "services" "mesa" "videoDrivers" ] [ "hardware" "opengl" "videoDrivers" ]
 
+++ obsolete [ "services" "mysql55" ] [ "services" "mysql" ]
+
 # Options that are obsolete and have no replacement.
 ++ obsolete' [ "boot" "loader" "grub" "bootDevice" ]
 ++ obsolete' [ "boot" "initrd" "luks" "enable" ]
diff --git a/nixos/modules/services/databases/mysql.nix b/nixos/modules/services/databases/mysql.nix
index 8be05a27cdcb..62fbc2a1415b 100644
--- a/nixos/modules/services/databases/mysql.nix
+++ b/nixos/modules/services/databases/mysql.nix
@@ -8,6 +8,10 @@ let
 
   mysql = cfg.package;
 
+  is55 = mysql.mysqlVersion == "5.5";
+
+  mysqldDir = if is55 then "${mysql}/bin" else "${mysql}/libexec";
+
   pidFile = "${cfg.pidDir}/mysqld.pid";
 
   mysqldOptions =
@@ -19,7 +23,7 @@ let
     [mysqld]
     ${optionalString (cfg.replication.role == "master" || cfg.replication.role == "slave") "log-bin=mysql-bin"}
     ${optionalString (cfg.replication.role == "master" || cfg.replication.role == "slave") "server-id = ${toString cfg.replication.serverId}"}
-    ${optionalString (cfg.replication.role == "slave")
+    ${optionalString (cfg.replication.role == "slave" && !is55)
     ''
       master-host = ${cfg.replication.masterHost}
       master-user = ${cfg.replication.masterUser}
@@ -47,7 +51,8 @@ in
       };
 
       package = mkOption {
-        default = pkgs.mysql;
+        type = types.package;
+        example = literalExample "pkgs.mysql";
         description = "
           Which MySQL derivation to use.
         ";
@@ -176,7 +181,7 @@ in
             chown -R ${cfg.user} ${cfg.pidDir}
           '';
 
-        serviceConfig.ExecStart = "${mysql}/libexec/mysqld --defaults-extra-file=${myCnf} ${mysqldOptions}";
+        serviceConfig.ExecStart = "${mysqldDir}/mysqld --defaults-extra-file=${myCnf} ${mysqldOptions}";
 
         postStart =
           ''
@@ -216,6 +221,16 @@ in
                     fi
                   '') cfg.initialDatabases}
 
+                ${optionalString (cfg.replication.role == "slave" && is55)
+                  ''
+                    # Set up the replication master
+
+                    ( echo "stop slave;"
+                      echo "change master to master_host='${cfg.replication.masterHost}', master_user='${cfg.replication.masterUser}', master_password='${cfg.replication.masterPassword}';"
+                      echo "start slave;"
+                    ) | ${mysql}/bin/mysql -u root -N
+                  ''}
+
                 ${optionalString (cfg.initialScript != null)
                   ''
                     # Execute initial script
diff --git a/nixos/modules/services/databases/mysql55.nix b/nixos/modules/services/databases/mysql55.nix
deleted file mode 100644
index fe8b29e3c6b7..000000000000
--- a/nixos/modules/services/databases/mysql55.nix
+++ /dev/null
@@ -1,248 +0,0 @@
-{ config, pkgs, ... }:
-
-with pkgs.lib;
-
-let
-
-  cfg = config.services.mysql55;
-
-  mysql = cfg.package;
-
-  pidFile = "${cfg.pidDir}/mysqld.pid";
-
-  mysqldOptions =
-    "--user=${cfg.user} --datadir=${cfg.dataDir} " +
-    "--pid-file=${pidFile}";
-
-  myCnf = pkgs.writeText "my.cnf"
-  ''
-    [mysqld]
-    ${optionalString (cfg.replication.role == "master" || cfg.replication.role == "slave") "log-bin=mysql-bin"}
-    ${optionalString (cfg.replication.role == "master" || cfg.replication.role == "slave") "server-id = ${toString cfg.replication.serverId}"}
-    ${cfg.extraOptions}
-  '';
-
-in
-
-{
-
-  ###### interface
-
-  options = {
-
-    services.mysql55 = {
-
-      enable = mkOption {
-        default = false;
-        description = "
-          Whether to enable the MySQL server.
-        ";
-      };
-
-      package = mkOption {
-        default = pkgs.mysql55;
-        description = "
-          Which MySQL derivation to use.
-        ";
-      };
-
-      port = mkOption {
-        default = "3306";
-        description = "Port of MySQL";
-      };
-
-      user = mkOption {
-        default = "mysql";
-        description = "User account under which MySQL runs";
-      };
-
-      dataDir = mkOption {
-        default = "/var/mysql"; # !!! should be /var/db/mysql
-        description = "Location where MySQL stores its table files";
-      };
-
-      pidDir = mkOption {
-        default = "/var/run/mysql";
-        description = "Location of the file which stores the PID of the MySQL server";
-      };
-
-      extraOptions = mkOption {
-        default = "";
-        example = ''
-          key_buffer_size = 6G
-          table_cache = 1600
-          log-error = /var/log/mysql_err.log
-        '';
-        description = ''
-          Provide extra options to the MySQL configuration file.
-
-          Please note, that these options are added to the
-          <literal>[mysqld]</literal> section so you don't need to explicitly
-          state it again.
-        '';
-      };
-
-      initialDatabases = mkOption {
-        default = [];
-        description = "List of database names and their initial schemas that should be used to create databases on the first startup of MySQL";
-        example = [
-          { name = "foodatabase"; schema = literalExample "./foodatabase.sql"; }
-          { name = "bardatabase"; schema = literalExample "./bardatabase.sql"; }
-        ];
-      };
-
-      initialScript = mkOption {
-        default = null;
-        description = "A file containing SQL statements to be executed on the first startup. Can be used for granting certain permissions on the database";
-      };
-
-      # FIXME: remove this option; it's a really bad idea.
-      rootPassword = mkOption {
-        default = null;
-        description = "Path to a file containing the root password, modified on the first startup. Not specifying a root password will leave the root password empty.";
-      };
-
-      replication = {
-        role = mkOption {
-          default = "none";
-          description = "Role of the MySQL server instance. Can be either: master, slave or none";
-        };
-
-        serverId = mkOption {
-          default = 1;
-          description = "Id of the MySQL server instance. This number must be unique for each instance";
-        };
-
-        masterHost = mkOption {
-          description = "Hostname of the MySQL master server";
-        };
-
-        masterUser = mkOption {
-          description = "Username of the MySQL replication user";
-        };
-
-        masterPassword = mkOption {
-          description = "Password of the MySQL replication user";
-        };
-
-        masterPort = mkOption {
-          default = 3306;
-          description = "Port number on which the MySQL master server runs";
-        };
-      };
-    };
-
-  };
-
-
-  ###### implementation
-
-  config = mkIf config.services.mysql55.enable {
-
-    users.extraUsers.mysql = {
-      description = "MySQL server user";
-      group = "mysql";
-      uid = config.ids.uids.mysql;
-    };
-
-    users.extraGroups.mysql.gid = config.ids.gids.mysql;
-
-    environment.systemPackages = [mysql];
-
-    systemd.services.mysql =
-      { description = "MySQL Server";
-
-        wantedBy = [ "multi-user.target" ];
-
-        unitConfig.RequiresMountsFor = "${cfg.dataDir}";
-
-        preStart =
-          ''
-            if ! test -e ${cfg.dataDir}/mysql; then
-                mkdir -m 0700 -p ${cfg.dataDir}
-                chown -R ${cfg.user} ${cfg.dataDir}
-                ${mysql}/bin/mysql_install_db ${mysqldOptions}
-                touch /tmp/mysql_init
-            fi
-
-            mkdir -m 0700 -p ${cfg.pidDir}
-            chown -R ${cfg.user} ${cfg.pidDir}
-          '';
-
-        serviceConfig.ExecStart = "${mysql}/bin/mysqld --defaults-extra-file=${myCnf} ${mysqldOptions}";
-
-        postStart =
-          ''
-            # Wait until the MySQL server is available for use
-            count=0
-            while [ ! -e /tmp/mysql.sock ]
-            do
-                if [ $count -eq 30 ]
-                then
-                    echo "Tried 30 times, giving up..."
-                    exit 1
-                fi
-
-                echo "MySQL daemon not yet started. Waiting for 1 second..."
-                count=$((count++))
-                sleep 1
-            done
-
-            if [ -f /tmp/mysql_init ]
-            then
-                ${concatMapStrings (database:
-                  ''
-                    # Create initial databases
-                    if ! test -e "${cfg.dataDir}/${database.name}"; then
-                        echo "Creating initial database: ${database.name}"
-                        ( echo "create database ${database.name};"
-                          echo "use ${database.name};"
-
-                          if [ -f "${database.schema}" ]
-                          then
-                              cat ${database.schema}
-                          elif [ -d "${database.schema}" ]
-                          then
-                              cat ${database.schema}/mysql-databases/*.sql
-                          fi
-                        ) | ${mysql}/bin/mysql -u root -N
-                    fi
-                  '') cfg.initialDatabases}
-                
-                ${optionalString (cfg.replication.role == "slave")
-                  ''
-                    # Set up the replication master
-                    
-                    ( echo "stop slave;"
-                      echo "change master to master_host='${cfg.replication.masterHost}', master_user='${cfg.replication.masterUser}', master_password='${cfg.replication.masterPassword}';"
-                      echo "start slave;"
-                    ) | ${mysql}/bin/mysql -u root -N
-                  ''}
-
-                ${optionalString (cfg.initialScript != null)
-                  ''
-                    # Execute initial script
-                    cat ${cfg.initialScript} | ${mysql}/bin/mysql -u root -N
-                  ''}
-
-                ${optionalString (cfg.rootPassword != null)
-                  ''
-                    # Change root password
-
-                    ( echo "use mysql;"
-                      echo "update user set Password=password('$(cat ${cfg.rootPassword})') where User='root';"
-                      echo "flush privileges;"
-                    ) | ${mysql}/bin/mysql -u root -N
-                  ''}
-
-              rm /tmp/mysql_init
-            fi
-          ''; # */
-
-        serviceConfig.ExecStop =
-          "${mysql}/bin/mysqladmin ${optionalString (cfg.rootPassword != null) "--user=root --password=\"$(cat ${cfg.rootPassword})\""} shutdown";
-      };
-
-  };
-
-}
diff --git a/pkgs/servers/sql/mariadb/default.nix b/pkgs/servers/sql/mariadb/default.nix
index e09943d86c8d..db6797a8d687 100644
--- a/pkgs/servers/sql/mariadb/default.nix
+++ b/pkgs/servers/sql/mariadb/default.nix
@@ -14,6 +14,8 @@ stdenv.mkDerivation rec {
 
   enableParallelBuilding = true;
 
+  passthru.mysqlVersion = "5.5";
+
   meta = {
     description = "An enhanced, drop-in replacement for MySQL";
     homepage    = https://mariadb.org/;
diff --git a/pkgs/servers/sql/mysql/5.1.x.nix b/pkgs/servers/sql/mysql/5.1.x.nix
index c210c9965327..c309158a6705 100644
--- a/pkgs/servers/sql/mysql/5.1.x.nix
+++ b/pkgs/servers/sql/mysql/5.1.x.nix
@@ -27,6 +27,8 @@ stdenv.mkDerivation rec {
       rm -rf $out/mysql-test $out/sql-bench $out/share/info
     '';
 
+  passthru.mysqlVersion = "5.1";
+
   meta = {
     homepage = http://www.mysql.com/;
     description = "The world's most popular open source database";
diff --git a/pkgs/servers/sql/mysql/5.5.x.nix b/pkgs/servers/sql/mysql/5.5.x.nix
index bd30b7db75ff..e8da8a48d65f 100644
--- a/pkgs/servers/sql/mysql/5.5.x.nix
+++ b/pkgs/servers/sql/mysql/5.5.x.nix
@@ -28,6 +28,8 @@ stdenv.mkDerivation rec {
     rm -rf $out/mysql-test $out/sql-bench
   '';
 
+  passthru.mysqlVersion = "5.5";
+
   meta = {
     homepage = http://www.mysql.com/;
     description = "The world's most popular open source database";