[root@iZwz98m7yqiqoatk3bc39fZ ~]# systemctl start mysqld
Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.
linux服务器上Mysql启动报错，找了很多资料，查看Mysql日志如下：
[root@iZwz98m7yqiqoatk3bc39fZ ~]# tail -200f /var/log/mysqld.log
2022-03-25T18:15:52.462587Z 0 [ERROR] InnoDB: mmap(137428992 bytes) failed; errno 12
2022-03-25T18:15:52.462593Z 0 [ERROR] InnoDB: Cannot allocate memory for the buffer pool
2022-03-25T18:15:52.462599Z 0 [ERROR] InnoDB: Plugin initialization aborted with error Generic error
2022-03-25T18:15:52.462608Z 0 [ERROR] Plugin 'InnoDB' init function returned error.
2022-03-25T18:15:52.462613Z 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2022-03-25T18:15:52.462618Z 0 [ERROR] Failed to initialize builtin plugins.
2022-03-25T18:15:52.462623Z 0 [ERROR] Aborting
最后找到了正确的解决方法。free指令查看内存：
[root@iZwz98m7yqiqoatk3bc39fZ ~]# free
total used free shared buff/cache available
Mem: 498432 230928 117024 528 150480 253864
Swap: 0 0 0
服务器没有配置Swap分区，关于Swap分区可以参见百度百科(Swap分区),知道了当前问题的源头就给机器配置一个Swap分区大小1G
[root@iZwz98m7yqiqoatk3bc39fZ ~]# sudo dd if=/dev/zero of=/swapfile bs=1M count=1024
1024 0 records in
1024 0 records out
1073741824 bytes (1.1 GB) copied, 9.10677 s, 118 MB/s
[root@iZwz98m7yqiqoatk3bc39fZ ~]# sudo mkswap /swapfile
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=7e142fa1-3db5-4e5f-9025-8a52166e9ee1
[root@iZwz98m7yqiqoatk3bc39fZ ~]# sudo swapon /swapfile
swapon: /swapfile: insecure permissions 0644, 0600 suggested.
[root@iZwz98m7yqiqoatk3bc39fZ ~]# free
total used free shared buff/cache available
Mem: 498432 231512 5884 528 261036 253296
Swap: 1048572 0 1048572
[root@iZwz98m7yqiqoatk3bc39fZ ~]# systemctl start mysqld.service
问题解决！
