Improve performance

We have migrated from owncloud 8.2 with php 5.5.9 to php7 and nextcloud 13 on April 15 2018. Users have been informed here https://www.fairkom.eu/fairkom-owncloud-ist-nun-nextcloud-umstellung-montag-164-13-uhr nextcloud 13 is supposed to be much faster and php7 should also be a gain, see https://owncloud.org/news/php-7-is-here-and-owncloud-is-ready/

But the user experience is slower. This issue is to analyse potential bottlenecks. See also https://docs.nextcloud.com/server/13/admin_manual/configuration_server/server_tuning.html?highlight=redis

• PHP opcache
• offload DB to heu13 or extra LV
• php fpm https://docs.nextcloud.com/server/13/admin_manual/installation/source_installation.html#php-fpm-configuration-notes - not possible on this Apache version
• redis file locking support