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路径确实没问题,而且目录和目录下所有文件都是777权限,上层目录也有rx权限,只不过datadir和下属文件owner都是root(因为我用虚拟机挂载的windows的文件系统)。后来想到应该是selinux搞的鬼,设置为permissive模式之后正常启动mysqld。