Johnny Withers wrote: > I hope someone can help me out here. I'm having trouble with some new > servers and memory allocation. > > Some basic specs on the servers: > 32GB total mem > 2GB swap > 64-bit RHEL > 64-bit mysqld > overcommit_memory=2 > > mysql fails to start with 14GB innodb_buffer_pool_size > mysql will start with 12GB buffer pool setting > When overcommit_memory is set to 0, mysql starts with 26GB buffer pool.
This is due to a system-wide limitation on the amount of memory that can be allocated by processes that the Linux kernel imposes when overcommit is disabled. The limit is (amount of swap) + (percentage of physical memory), and the default percentage is 50. So the limit in your case is 2G + 16G == 18G for all processes together; 14G for innodb_buffer_pool_size is too much. You can increase the amount of swap, or increase the percentage (via /proc/sys/vm/overcommit_ratio, which isn't as well-known, though it is in the kernel documentation). Hope that helps. Charles -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
