I have successfully installed moodle on two dedicated virtual private servers with a hosting company here in the UK (Supanames) and they are running fine. But now with a third server I am having problems with occasionally very slow moodle subwebs.
The subwebs are moodle only and are just for limited demo use of 10 users or so, but they all get very slow for a few hours.
I am running moodle 1.9.3 on them and using PLESK and VIRTUOZZO for administration. When I reconfigured the webservmgr today with a 5th subweb again the system has slowed down so that all subweb moodle pages (even just the logon page) can take around 3 minutes to load.
There is plenty of memory set in the php ini config, PHPINFO shows 96MB. When this has happened in the past the server speeded back up to normal a day later.
The hosting company told me they had run TOP and apache was using a lot of resources when the problem happened before and I attached a screenshot of TOP results but meanwhile I hoped that someone might have some ideas or a similar experience or some advice.
Thanks for any assistance received
PS Things I am thinking about
1) The moodle cron job is simultaneous every 30 mins for all 5 subwebs could that be an issue, maybe I should stagger them
2) Is there some kind of bug with PLESK or my Vhosts.config files
3) When I rebuild the PLESK config file with websrvmgr command could that iniate a problem
4) Could there be a bug in the Themes I'm using (although they are just the Standard logo and Moodle Barcelona themes)