[horde] Extremely slow kronolith on a CentOS 6.5 VM server

[Louis-Philippe Allard]

Hi,

I am facing a performance issue on a CentOS 6.5 virtual server where
kronolith is extremely slow (takes 15+ seconds to load an event),
navigating the calendar is also almost unusable.

Server runs for a single user with lightly loaded calendar.

[serveruser at centos ~]$ httpd -v
Server version: Apache/2.2.15 (Unix)
Server built:   Apr  3 2014 23:56:16

[serveruser at centos ~]$ php -v
PHP 5.3.3 (cli) (built: Dec 11 2013 03:29:57)
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies

[serveruser at centos ~]$ mysql -V
mysql  Ver 14.14 Distrib 5.1.73, for redhat-linux-gnu (x86_64) using
readline 5.1

Server is not overloaded in any ways (8 cores at 3.1GHz, 52GB RAM) and
shows normal to moderate SQL activity.

No errors in httpd_error.log or in mysqld.log.

How can I troubleshoot this?

Thanks!