title: mysql server does not use all available RAM
body: <pre><code>[mysqld]
  open_files_limit=10000
  skip-name-resolve
  datadir=/var/lib/mysql
  socket=/var/lib/mysql/mysql.sock
  user=mysql
  max_heap_table_size = 2GB
  query_cache_limit = 256M
  key_buffer_size = 6GB
  innodb_table_locks = 0
  innodb_buffer_pool_size = 100M
  join_buffer_size = 32M
  max_connections = 400
  max_user_connections = 1400
  #skip-bdb
  key_buffer = 48M
  # max_allowed_packet = 68M
  max_allowed_packet = 256M
  tmp_table_size = 3GB
  table_cache = 800
  sort_buffer_size = 1M
  net_buffer_length = 8K
  read_buffer_size = 1M
  read_rnd_buffer_size = 512K
  myisam_sort_buffer_size = 8M
  server-id  = 1
  wait_timeout = 28800
  query_cache_size = 50M
  thread_cache_size = 1024
  long_query_time = 4
  </code></pre>
  
  <p>We have this config on 15GB RAM VPS server, which is used for MySQL only. The problem is that the server is using only 3GB of RAM during the heaviest traffic.</p>
  
  <p>Can anyone suggest what should be adjusted in config to use all available RAM?</p>
  
  <p>mysqltuner.pl says this:
  [!!] Maximum possible memory usage: 15.0G (103% of installed RAM)</p>