省流：
挂载的话，使用 /etc/fstab
正文：
在企业中，服务器重启，有时候会遇到mysql 启动报错 Can`t change dir to 'xxx', No such file or directory。大致意思是无法将目录换成xxx，因为没有这个目录。
原因通常是配置文件配置的目录有问题，或者挂载盘加载慢于mysql启动（mysql的data数据放在挂载盘里）
linux中配置文件是my.cnf，通常路径是 /etc/my.cnf
windows中配置文件是my.ini，
mysql配置文件大致内容如下：
# mysql路径
basedir=/sata09/data/mysql
# mysql存数据的路径
datadir=/sata09/data/mysql/data这篇文章以挂载问题导致为例。
挂载有两种：
rc.local，fstab。最好使用fstab，原因如下：
我之前的挂载命令是放在/etc/rc.local，现在需要放在/etc/fstab
mount /prd/ssd/ssd01 /ssd01
mount /prd/sata/sata01 /sata01详细日志如下：
Oct 17 02:50:32 ali5messrv1 mysqld: mysqld: Can`t change dir to '/sata09/data/mysql/' (Errcode: 2 - No such file or directory)
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060197Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060311Z 0 [Warning] Can`t create test file /sata09/data/mysql/ali5messrv1.lower-test
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060344Z 0 [Note] /usr/sbin/mysqld (mysqld 5.7.32-log) starting as process 3280 ...
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060369Z 0 [ERROR] Can`t find error-message file '/sata09/data/mysql/share/mysql/errmsg.sys'. Check error-message file location and 'lc-messages-dir' configuration directive.
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060943Z 0 [Warning] Can`t create test file /sata09/data/mysql/ali5messrv1.lower-test
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060950Z 0 [Warning] Can`t create test file /sata09/data/mysql/ali5messrv1.lower-test
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060990Z 0 [ERROR] failed to set datadir to /sata09/data/mysql/
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060998Z 0 [ERROR] Aborting
Oct 17 02:50:32 ali5messrv1 systemd[1]: Starting MySQL Server...
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: mysqld: Can't create directory '/sata09/data/mysql/' (Errcode: 2 - No s...tory)
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: 2023-10-16T18:50:32.867006Z 0 [Warning] TIMESTAMP with implicit DEFAULT...ils).
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: 2023-10-16T18:50:32.867111Z 0 [ERROR] Can't find error-message file '/s...tive.
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: 2023-10-16T18:50:32.867941Z 0 [ERROR] Aborting
Oct 17 02:52:03 ali5messrv1 systemd[1]: Started MySQL Server.开机挂载mount etc/fstab与/etc/rc.d/rc.local区别-阿里云开发者社区
Oct 17 02:50:32 ali5messrv1 mysqld: mysqld: Can't change dir to '/sata09/data/mysql/' (Errcode: 2 - No such file or directory)
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060197Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060311Z 0 [Warning] Can't create test file /sata09/data/mysql/ali5messrv1.lower-test
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060344Z 0 [Note] /usr/sbin/mysqld (mysqld 5.7.32-log) starting as process 3280 ...
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060369Z 0 [ERROR] Can't find error-message file '/sata09/data/mysql/share/mysql/errmsg.sys'. Check error-message file location and 'lc-messages-dir' configuration directive.
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060943Z 0 [Warning] Can't create test file /sata09/data/mysql/ali5messrv1.lower-test
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060950Z 0 [Warning] Can't create test file /sata09/data/mysql/ali5messrv1.lower-test
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060990Z 0 [ERROR] failed to set datadir to /sata09/data/mysql/
Oct 17 02:50:32 ali5messrv1 mysqld: 2023-10-16T18:50:32.060998Z 0 [ERROR] Aborting
Oct 17 02:50:32 ali5messrv1 systemd[1]: Starting MySQL Server...
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: mysqld: Can't create directory '/sata09/data/mysql/' (Errcode: 2 - No s...tory)
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: 2023-10-16T18:50:32.867006Z 0 [Warning] TIMESTAMP with implicit DEFAULT...ils).
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: 2023-10-16T18:50:32.867111Z 0 [ERROR] Can't find error-message file '/s...tive.
Oct 17 02:50:32 ali5messrv1 mysqld_pre_systemd[2476]: 2023-10-16T18:50:32.867941Z 0 [ERROR] Aborting
Oct 17 02:52:03 ali5messrv1 systemd[1]: Started MySQL Server.