[ERROR] Can't start server: can't check PID filepath: No such file or directory

mysql 5.7启动不了

这个问题一般都是pid目录没创建或者没有目录权限
解决办法：创建pid目录并给予权限或修改pid目录（参看配置文件my.cnf默认为/etc/my.cnf）至mysql目录下

• 启动方法 由于密码忘记了（–skip-grant-tables）

[root@NGINX ~]# /usr/local/mysql/bin/mysqld_safe --skip-grant-tables --user=mysql &
[1] 24106
[root@NGINX ~]# 2020-02-03T18:17:41.676610Z mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
2020-02-03T18:17:41.706108Z mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
2020-02-03T18:17:42.156327Z mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended

[1]+  Done                    /usr/local/mysql/bin/mysqld_safe --skip-grant-tables --user=mysql
###查看端口状态发现没起来
 [root@NGINX ~]#netstat -nutpl |grep 3306
 [root@NGINX ~]#

• 查看故障日志
  故障日志存储位置请参考/etc/my.cnf中的log-error参数

### 查看配置文件参数 cat查看vi more等命令
[root@NGINX ~]# vi /etc/my.cnf
[mysqld]
datadir=/usr/local/mysql/data
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd

[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid

#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d
####日志报错信息###############
[root@NGINX ~]# cat /var/log/mariadb/mariadb.log

2020-02-03T18:17:41.948351Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2020-02-03T18:17:41.948457Z 0 [Note] --secure-file-priv is set to NULL. Operations related to importing and exporting data are disabled
2020-02-03T18:17:41.948567Z 0 [Note] /usr/local/mysql/bin/mysqld (mysqld 5.7.29) starting as process 24256 ...
2020-02-03T18:17:41.955264Z 0 [Note] InnoDB: PUNCH HOLE support available
2020-02-03T18:17:41.955304Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2020-02-03T18:17:41.955309Z 0 [Note] InnoDB: Uses event mutexes
2020-02-03T18:17:41.955312Z 0 [Note] InnoDB: GCC builtin __sync_synchronize() is used for memory barrier
2020-02-03T18:17:41.955316Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-02-03T18:17:41.955319Z 0 [Note] InnoDB: Using Linux native AIO
2020-02-03T18:17:41.955700Z 0 [Note] InnoDB: Number of pools: 1
2020-02-03T18:17:41.955832Z 0 [Note] InnoDB: Using CPU crc32 instructions
2020-02-03T18:17:41.958114Z 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2020-02-03T18:17:41.969536Z 0 [Note] InnoDB: Completed initialization of buffer pool
2020-02-03T18:17:41.973272Z 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2020-02-03T18:17:41.986619Z 0 [Note] InnoDB: Highest supported file format is Barracuda.
2020-02-03T18:17:41.999938Z 0 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
2020-02-03T18:17:41.999960Z 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-02-03T18:17:42.000076Z 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-02-03T18:17:42.020491Z 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2020-02-03T18:17:42.021802Z 0 [Note] InnoDB: 96 redo rollback segment(s) found. 96 redo rollback segment(s) are active.
2020-02-03T18:17:42.021820Z 0 [Note] InnoDB: 32 non-redo rollback segment(s) are active.
2020-02-03T18:17:42.022080Z 0 [Note] InnoDB: Waiting for purge to start
2020-02-03T18:17:42.072756Z 0 [Note] InnoDB: 5.7.29 started; log sequence number 2629979
2020-02-03T18:17:42.073073Z 0 [Note] Plugin 'FEDERATED' is disabled.
2020-02-03T18:17:42.089236Z 0 [Note] Found ca.pem, server-cert.pem and server-key.pem in data directory. Trying to enable SSL support using them.
2020-02-03T18:17:42.089291Z 0 [Note] Skipping generation of SSL certificates as certificate files are present in data directory.
2020-02-03T18:17:42.092945Z 0 [Warning] CA certificate ca.pem is self signed.
2020-02-03T18:17:42.093091Z 0 [Note] Skipping generation of RSA key pair as key files are present in data directory.
2020-02-03T18:17:42.093982Z 0 [Note] InnoDB: Loading buffer pool(s) from /usr/local/mysql/data/ib_buffer_pool
2020-02-03T18:17:42.101517Z 0 [Note] InnoDB: Buffer pool(s) load completed at 200203 13:17:42
2020-02-03T18:17:42.101931Z 0 [Note] Server hostname (bind-address): '*'; port: 3306
2020-02-03T18:17:42.102132Z 0 [Note] IPv6 is available.
2020-02-03T18:17:42.102162Z 0 [Note]   - '::' resolves to '::';
2020-02-03T18:17:42.102230Z 0 [Note] Server socket created on IP: '::'.
2020-02-03T18:17:42.104243Z 0 [ERROR] Can't start server: can't check PID filepath: No such file or directory

• 创建pid目录

[root@NGINX ~]# mkdir -p /var/run/mariadb/
[root@NGINX ~]# chown mysql.mysql /var/run/mariadb/ -R

• 重新启动

 [root@NGINX ~]# /usr/local/mysql/bin/mysqld_safe --skip-grant-tables --user=mysql &
[1] 24488
[root@NGINX ~]# 2020-02-03T18:24:19.611951Z mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
2020-02-03T18:24:19.643658Z mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
[root@NGINX ~]# netstat -nutpl |grep 330
tcp6       0      0 :::3306                 :::*                    LISTEN      24638/mysqld        
[root@NGINX ~]# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.29 MySQL Community Server (GPL)
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Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
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