We have a large number (2,500+) of databases and users in MySQL 5.6 on a single virtualized server (4 cpus and 8GB of memory). All the tables are using InnoDB. The actual data size is not very large (~5GB), and queries per second is low, just lots of small databases and users. Each account created for our application get's their own database and user (this architecture cannot change unfortunately).
We are seeing very poor performance, especially when trying to stop mysqld (often times it just times-out). Starting mysqld and spawning (ready for connections) takes over 3+ minutes. Running mysqldump brings the entire server to its knees. Load, CPU usage, and iowait, all skyrocket during mysqldump, and cause other queries to timeout and fail.
It was recommend that we transition off of using
innodb_file_per_table because of the excessive number of open file descriptors, shear number of directories and files, and i/o operations.
innodb_file_per_table to off does this, but how can we convert all existing databases and tables to utilize this?
Below is our current
/etc/my.conf just for reference, in-case there are further optimizations we can make to optimize for lots of small databases.
[mysqld] datadir=/mysql/data socket=/mysql/mysqld.sock symbolic-links=0 default-storage-engine=InnoDB slow_query_log=1 long_query_time=2 slow_query_log_file=/var/log/mysql_slow.log expire_logs_days=30 max_connections=50 bind-address=192.241.X.X port=3306 max_allowed_packet=4M net_retry_count=5 max_connect_errors=100 wait_timeout=14400 connect_timeout=10 open_files_limit=65535 innodb_open_files=65535 key_buffer_size=256M innodb_buffer_pool_size=4096M innodb_log_buffer_size=4M group_concat_max_len=16k max_sort_length=16k max_length_for_sort_data=16k query_cache_type=1 query_cache_limit=1M query_cache_size=64M innodb_thread_concurrency=8 thread_concurrency=8 thread_cache_size=128 thread_stack=1M read_buffer_size=1M join_buffer_size=1M sort_buffer_size=1M read_rnd_buffer_size=1M table_open_cache=32768 table_definition_cache=65535 tmp_table_size=33554432 max_heap_table_size=33554432 innodb_log_file_size=1024M innodb_flush_log_at_trx_commit=2 innodb_file_per_table log-warnings innodb_flush_neighbors=0 user=mysql old_passwords=0 [mysqld_safe] syslog pid-file=/var/run/mysqld/mysqld.pid