external - Apache/PHP not being able to access mounted drive -

i'm trying access mounted drive within php/apache (lamp @ centos). instance doing scandir:

scandir($dir); 

although works fine directory on same physical disc apache installed @ (including root, var, etc, ..), not work external mounted disks:

scandir('/var/log'); on local drive holds /var/www/html

delivers valid output, whereas

scandir('/mnt/data'); (which mount external fs) doesn't.

i have been experimenting filesystem permissions , httpd.conf directives (alias / directory), have not been able find solution yet.

can point me direction of how access external drives (/mnt/whatever) apache/php? thx!

if process can see mount point able access files within provided permissions, including acls , mac system allow it (mac here referring mandatory access control systems, i.e. selinux , apparmor).

either permissions need changed or webserver running in chroot environment (e.g. sees / /var/websrv/) or have not made right changes httpd config.

since you've provided no details of how system configured not you've tried not possible more specific.