网站环境升级，由于dedecms版本中php5.4中经常中文白页，只有选择低版本的lampp,决定使用lampp1.7.7，解压缩后在启动lampp时提示mysql无法启动。
查看/opt/lampp/var/mysql/www.centos.error文件，报错内容如下：
141109 11:10:19 mysqld_safe Starting mysqld daemon with databases from /opt/lamp
p/var/mysql
141109 11:10:19 [Note] Plugin 'FEDERATED' is disabled.
/opt/lampp/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
141109 11:10:19 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgr
ade to create it.
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use InnoDB's own implementation
InnoDB: Compressed tables use zlib 1.2.3
141109 11:10:19 InnoDB: Initializing buffer pool, size = 16.0M
141109 11:10:19 InnoDB: Completed initialization of buffer pool
141109 11:10:19 InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name /opt/lampp/var/mysql/ibdata1
InnoDB: File operation call: 'create'.
InnoDB: Cannot continue operation.
141109 11:10:19 mysqld_safe mysqld from pid file /opt/lampp/var/mysql/www.centos
.pid ended
根据提示，在Plugin和mysqld_safe上研究了半天也没有结果，只好尝试检查一下权限的问题
[root@www bin]# ll /opt/lampp/var/mysql
总用量 28
drwx------ 2 root root 4096 11月 9 11:10 cdcol
drwx------ 2 root root 4096 11月 9 11:10 mysql
-rw-r--r-- 1 root root 5 11月 9 11:10 mysql_upgrade_info
drwx------ 2 root root 4096 11月 9 11:10 performance_schema
drwx------ 2 root root 4096 11月 9 11:10 phpmyadmin
drwx------ 2 root root 4096 11月 9 11:10 test
-rw-rw---- 1 nobody root 974 11月 9 11:10 www.centos.err
看到了吗？mysql工作目录的权限跟mysql创建的文件的权限不一致，修改目录权限为nobody.root试试
[root@www bin]# chown -R nobody.root /opt/lampp/var/mysql
[root@www bin]# /opt/lampp/lampp startmysql
XAMPP: Starting MySQL...
[root@www bin]#
终于启动成功了。
