{ config, pkgs, ... }:
let
  mysqlenv-rsync       = pkgs.buildEnv { name = "mysql-path-env-rsync";       pathsToLink = [ "/bin" ]; paths = with pkgs; [ mariadb bash which gawk gnutar procps rsync lsof ]; };
  mysqlenv-mariabackup = pkgs.buildEnv { name = "mysql-path-env-mariabackup"; pathsToLink = [ "/bin" ]; paths = with pkgs; [ mariadb bash which gawk gnutar procps inetutils glibc.bin socat iproute pv openssl netcat inetutils ]; };
  mysqlenv-xtrabackup  = pkgs.buildEnv { name = "mysql-path-env-xtrabackup";  pathsToLink = [ "/bin" ]; paths = with pkgs; [ mariadb bash which gawk gnutar procps inetutils percona-xtrabackup socat iproute pv openssl netcat ]; };

in
{
  environment.systemPackages = with pkgs; [
    mariadb mariadb.client percona-xtrabackup
  ];

  systemd.services.mysql = with pkgs; {
    path = [ mysqlenv-xtrabackup ];
  };

  services.mysql = {
    enable = true;
    package = pkgs.mariadb;
    dataDir = "/var/data/db/mysql";
    extraOptions = ''
      bind-address = 0.0.0.0
      innodb_log_file_size = 128M
      innodb_file_per_table = 1
      character-set-server = utf8
      default-storage-engine = InnoDB
      wait_timeout = 600
      max_allowed_packet = 32M
      symbolic-links=0

      log-warnings = 2
      log_error = /var/data/db/logs/mysql_error.log
      slow_query_log_file = /var/data/db/logs/mysql_slow.log
      slow_query_log = 1
      long_query_time = 1

      query_cache_size = 24M
      query_cache_limit = 6MB
      key_buffer_size = 5M
      #key_cache_division_limit=70
      max_connections = 40
      max_heap_table_size = 290M
      tmp_table_size = 290M
      join_buffer_size = 3M
      table_open_cache = 600
      table_definition_cache = 600
      skip_name_resolve
      skip_host_cache

      [galera]
      wsrep_on=ON
      binlog_format=ROW
      innodb_autoinc_lock_mode=2
      innodb_locks_unsafe_for_binlog=1
      query_cache_size=0
      query_cache_type=0
      default_storage_engine=InnoDB
      innodb_log_file_size=128M
      innodb_file_per_table
      innodb_flush_log_at_trx_commit=2
      wsrep_provider=${pkgs.mariadb.galera}/lib/galera/libgalera_smm.so
      wsrep_cluster_address="gcomm://192.168.1.21,192.168.1.22,192.168.1.23"
      wsrep_cluster_name='galera_cluster'
      wsrep_node_address='192.168.1.21'
      wsrep_node_name='KVM-1'
      wsrep_sst_method=xtrabackup-v2
      wsrep_sst_auth=repl_user:user_repl
      wsrep_debug=ON

      [mysqld_safe]
      log-error = /var/data/db/logs/mysql_error.log

      [mysqldump]
      quick
      max_allowed_packet = 16M

      [myisamchk]
      key_buffer_size = 256M
      sort_buffer_size = 256M
      read_buffer = 2M
      write_buffer = 2M

      [mysqlhotcopy]
      interactive-timeout
    '';
  };
} 

git:(8d6746a4bf4)# nix build -f ~/works/src_nix/nixpkgs_my mariadb.galera                                                                 
[3 built, 209 copied (914.4 MiB), 158.8 MiB DL]
time: 265