120710 11:01:38 InnoDB: Initializing buffer pool, size = 8.0G
InnoDB: mmap(8791261184 bytes) failed; errno 12
120710 11:01:38 InnoDB: Completed initialization of buffer pool
120710 11:01:38 InnoDB: Fatal error: cannot allocate memory for the buffer pool
120710 11:01:38 [ERROR] Plugin 'InnoDB' init function returned error.
120710 11:01:38 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
120710 11:01:38 [ERROR] Unknown/unsupported storage engine: InnoDB
120710 11:01:38 [ERROR] Aborting
从err日志，可以看出，我分配的Initializing buffer pool, size = 8.0G，使得机器无法初始化。导致mysql启动不起来。
这个值=>my.cnf的innodb_buffer_pool_size
只要重新设置innodb_buffer_pool_size即可。官方文档默认值给出的是128M，如下图所示。
InnoDB: mmap(8791261184 bytes) failed; errno 12
120710 11:01:38 InnoDB: Completed initialization of buffer pool
120710 11:01:38 InnoDB: Fatal error: cannot allocate memory for the buffer pool
120710 11:01:38 [ERROR] Plugin 'InnoDB' init function returned error.
120710 11:01:38 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
120710 11:01:38 [ERROR] Unknown/unsupported storage engine: InnoDB
120710 11:01:38 [ERROR] Aborting
从err日志，可以看出，我分配的Initializing buffer pool, size = 8.0G，使得机器无法初始化。导致mysql启动不起来。
这个值=>my.cnf的innodb_buffer_pool_size
只要重新设置innodb_buffer_pool_size即可。官方文档默认值给出的是128M，如下图所示。
| Name | Old Default | New Default |
|---|---|---|
| innodb_additional_mem_pool_size | 1MB | 8MB |
| innodb_buffer_pool_size | 8MB | 128MB |
| innodb_change_buffering | inserts | all |
| innodb_file_format_check | ON | 1 |
| innodb_log_buffer_size | 1MB | 8MB |
| innodb_max_dirty_pages_pct | 90 | 75 |
| innodb_sync_spin_loops | 20 | 30 |
| innodb_thread_concurrency | 8 | 0 |
