Looking for a civicrm/drupal expert for performance improvements

[Nico Klein]

Can someone help me with performance improvements for our new and first production website made by drupal/civicrm.
There are 4 servers all with ubuntu 14.04.2 LTS
1x proxy with haproxy
1x webserver with apache (Apache/2.4.7), PHP (PHP 5.5.9-1ubuntu4.7 (cli) (built: Mar 16 2015 20:47:39), curl (curl 7.35.0 (x86_64-pc-linux-gnu) libcurl/7.35.0 OpenSSL/1.0.1f zlib/1.2.8 libidn/1.28 librtmp/2.3), drupal (7.32), civicrm (4.4.8 ) and a lot more modules.
1x mysql server (Ver 14.14 Distrib 5.5.41, for debian-linux-gnu (x86_64) using readline 6.3
1x solr server

Al servers are installed on a vm enviroment (vmware 5.5)

Please contact my my email nico.klein@pum.nl or by phone +31 (0)70 349 05 33