centos6.2，停止mysqld然後修改/etc/my.cnf datadir的位置，啟動mysqld提示FAILED，查看日志
代碼如下:
120609 11:31:31 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
120609 11:35:12 mysqld_safe Starting mysqld daemon with databases from /mnt/hgfs/mysql_data
120609 11:35:13 [Warning] Can't create test file /mnt/hgfs/mysql_data/data.lower-test
120609 11:35:13 [Warning] Can't create test file /mnt/hgfs/mysql_data/data.lower-test
/usr/libexec/mysqld: Can't change dir to '/mnt/hgfs/mysql_data/' (Errcode: 13)
120609 11:35:13 [ERROR] Aborting
120609 11:35:13 [Note] /usr/libexec/mysqld: Shutdown complete
120609 11:35:13 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
新的datadir路徑確實沒問題，而且目錄和目錄下所有文件都是777權限，上層目錄也有rx權限，只不過datadir和下屬文件owner都是root（因為我用虛擬機掛載的windows的文件系統）。後來想到應該是selinux搞的鬼，設置為permissive模式之後正常啟動mysqld。
代碼如下:
[root@data selinux]# getenforce
Enforcing
[root@data selinux]# setenforce 0
[root@data selinux]# getenforce
Permissive
setenforce 1 設置SELinux 成為enforcing模式
setenforce 0 設置SELinux 成為permissive模式
徹底關閉，vi /etc/selinux/config 修改 SELINUX=disabled
代碼如下:
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# mls - Multi Level Security protection.
SELINUXTYPE=targeted
