Directadmin默认安装好zend并没有开启，如何开启zend呢？下面是具体方法 

第一步，进入da目录,修改options.conf 

[root@my2 ~]# cd /usr/local/directadmin/custombuild/ 
[root@my2 custombuild]# vi options.conf 

第二步，找到zend = no改成zend =yes，然后再执行./build zend，完成后会看到下面的提示 

[root@my2 custombuild]# ./build zend 
File already exists: ZendOptimizer-3.3.3-linux-glibc23-i386.tar.gz 
Zend Optimizer has been installed. 

第三步，然后重启下apache即可

 [root@my2 ~]# service httpd restart 

第四步，查看 

[root@my2 ~]# php -v 
PHP 5.2.17 (cli) (built: May 22 2012 02:47:56) 
Copyright (c) 1997-2010 The PHP Group Zend Engine v2.2.0,
 Copyright (c) 1998-2010 Zend Technologies with Zend Optimizer v3.3.3, 
Copyright (c) 1998-2007, by Zend Technologies