5 files changed, 19 insertions, 15 deletions
diff --git a/nixos/modules/services/databases/memcached.nix b/nixos/modules/services/databases/memcached.nix
index 84d2c8674f4e..d1dfdb41bf40 100644
--- a/nixos/modules/services/databases/memcached.nix
+++ b/nixos/modules/services/databases/memcached.nix
@@ -67,6 +67,7 @@ in
     users.users = optional (cfg.user == "memcached") {
       name = "memcached";
       description = "Memcached server user";
+      isSystemUser = true;
     };
 
     environment.systemPackages = [ memcached ];
diff --git a/nixos/modules/services/databases/mysql.nix b/nixos/modules/services/databases/mysql.nix
index df74cfc9a26b..39192d059485 100644
--- a/nixos/modules/services/databases/mysql.nix
+++ b/nixos/modules/services/databases/mysql.nix
@@ -272,8 +272,13 @@ in
       port = ${toString cfg.port}
       datadir = ${cfg.dataDir}
       ${optionalString (cfg.bind != null) "bind-address = ${cfg.bind}" }
-      ${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}"}
+      ${optionalString (cfg.replication.role == "master" || cfg.replication.role == "slave")
+      ''
+        log-bin=mysql-bin-${toString cfg.replication.serverId}
+        log-bin-index=mysql-bin-${toString cfg.replication.serverId}.index
+        relay-log=mysql-relay-bin
+        server-id = ${toString cfg.replication.serverId}
+      ''}
       ${optionalString (cfg.ensureUsers != [])
       ''
         plugin-load-add = auth_socket.so
@@ -381,6 +386,7 @@ in
 
                         ( echo "stop slave;"
                           echo "change master to master_host='${cfg.replication.masterHost}', master_user='${cfg.replication.masterUser}', master_password='${cfg.replication.masterPassword}';"
+                          echo "set global slave_exec_mode='IDEMPOTENT';"
                           echo "start slave;"
                         ) | ${mysql}/bin/mysql -u root -N
                       ''}
diff --git a/nixos/modules/services/databases/postgresql.nix b/nixos/modules/services/databases/postgresql.nix
index 7bba4dacddcc..3bedfe96a180 100644
--- a/nixos/modules/services/databases/postgresql.nix
+++ b/nixos/modules/services/databases/postgresql.nix
@@ -226,7 +226,8 @@ in
       # Note: when changing the default, make it conditional on
       # ‘system.stateVersion’ to maintain compatibility with existing
       # systems!
-      mkDefault (if versionAtLeast config.system.stateVersion "17.09" then pkgs.postgresql_9_6
+      mkDefault (if versionAtLeast config.system.stateVersion "20.03" then pkgs.postgresql_11
+            else if versionAtLeast config.system.stateVersion "17.09" then pkgs.postgresql_9_6
             else if versionAtLeast config.system.stateVersion "16.03" then pkgs.postgresql_9_5
             else throw "postgresql_9_4 was removed, please upgrade your postgresql version.");
 
diff --git a/nixos/modules/services/databases/redis.nix b/nixos/modules/services/databases/redis.nix
index 9c389d80a6df..5695eeaf74cb 100644
--- a/nixos/modules/services/databases/redis.nix
+++ b/nixos/modules/services/databases/redis.nix
@@ -186,26 +186,21 @@ in
 
   config = mkIf config.services.redis.enable {
 
-    boot.kernel.sysctl = mkIf cfg.vmOverCommit {
-      "vm.overcommit_memory" = "1";
-    };
+    boot.kernel.sysctl = {
+      "vm.nr_hugepages" = "0";
+    } // mkIf cfg.vmOverCommit { "vm.overcommit_memory" = "1"; };
 
     networking.firewall = mkIf cfg.openFirewall {
       allowedTCPPorts = [ cfg.port ];
     };
 
-    users.users.redis.description = "Redis database user";
+    users.users.redis = {
+      description = "Redis database user";
+      isSystemUser = true;
+    };
 
     environment.systemPackages = [ cfg.package ];
 
-    systemd.services.disable-transparent-huge-pages = {
-      description = "Disable Transparent Huge Pages (required by Redis)";
-      before = [ "redis.service" ];
-      wantedBy = [ "redis.service" ];
-      script = "echo never > /sys/kernel/mm/transparent_hugepage/enabled";
-      serviceConfig.Type = "oneshot";
-    };
-
     systemd.services.redis =
       { description = "Redis Server";
 
diff --git a/nixos/modules/services/databases/rethinkdb.nix b/nixos/modules/services/databases/rethinkdb.nix
index 4828e594b328..f18fbaf5b062 100644
--- a/nixos/modules/services/databases/rethinkdb.nix
+++ b/nixos/modules/services/databases/rethinkdb.nix
@@ -99,6 +99,7 @@ in
     users.users.rethinkdb = mkIf (cfg.user == "rethinkdb")
       { name = "rethinkdb";
         description = "RethinkDB server user";
+        isSystemUser = true;
       };
 
     users.groups = optionalAttrs (cfg.group == "rethinkdb") (singleton