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Hereunder my hardware config:

CPU: 1x Intel Xeon X3470 Quad core @ 2.93GHz
RAM: 4x 8GB DDR3
Disks: 2 x SATA 320GB for the system & 4 x SAS 300GB for the DB

I've upgraded from 12Gb to 32Gb and switched the Java application server on another server in order to have a dedicated MySQL server.

Hereunder my MySQL config:

MySQL 5.5.28 with InnoDB plugin on RedHat 6. Database size is 130Gb.

  max_allowed_packet = 50M
  max_connections = 100
  back_log = 2048
  tmp_table_size = 300M
  max_heap_table_size = 300M
  sort_buffer_size = 40M
  read_buffer_size = 10M
  binlog_cache_size = 1M
  key_buffer_size = 10M
  table_open_cache = 4096
  table_definition_cache = 500
  open_files_limit = 65535
  thread_cache_size = 100
  query_cache_size = 500M
  innodb_additional_mem_pool_size = 50M
  innodb_buffer_pool_size = 28000M
  innodb_buffer_pool_instances = 5
  innodb_commit_concurrency = 0
  innodb_concurrency_tickets = 0
  innodb_fast_shutdown = 0
  innodb_flush_log_at_trx_commit = 2
  innodb_flush_method = O_DIRECT
  innodb_lock_wait_timeout = 50
  innodb_log_buffer_size = 128M
  innodb_log_file_size = 256M
  innodb_thread_concurrency = 0
  innodb_read_io_threads = 64
  innodb_write_io_threads = 64
  innodb_stats_on_metadata = 0
  performance_schema = 0

Since my RAM upgrade, I've updated "innodb_buffer_pool_size" from 8000M to 28000M. Since this upgrade, the response time for my SQL requests are a disaster (7x much slower).

What do you think ? Another options to update or to add ?

Many thanks in advance,


share|improve this question
How bad is "7x slower"? 2ms to 14ms, or 1 second to 7 seconds? An example of the queries that are worst affected might be useful. Also, 28GB is almost 90% of your system memory and it's possible that you're experiencing paging. Could you run "vmstat 5" for 20-30 seconds when your server is busy, and post the output? –  Nathan Jolly May 16 '13 at 0:17
I'm really sorry, we can close this topic. Indeed, the slow was due to the SSH tunnel. –  Bob Sauvage May 16 '13 at 12:18

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