SugarCRM is running very slow on GlusterFS

General information

OS: Debian 10.12

Suger Professional Version: 11.0.3

PHP Version: 7.3.12

GlusterFS Client/Server Version: 5.5-3

MariaDB Version: 10.4.16-MariaDB

Issue

AFTER moving the sugar webarchive (/var/www/html/sugar) from hdd to glusterfs mount we noticed a decreasing performance.
The response time for the login page alone increased from around 50ms to over 1s in average.
The other actions inside sugar are even slower and make it close to impossible to work with sugar properly.
Do you guys have experience in putting sugar (webarchive/php files) onto network file systems like GlusterFs ?
Is there anything that we can do to speed up the app performance ?