Recently another client of mine was having so many issues with his joomla site and this was really really driving him mad. The major problem was his host that keeps turning off his site due to the fact that it is causing overloading to the system on a shared hosting. Please note that this same topic was previously written about in this post here but this is just an update on a related issue.
Problem: Please see a list of problems that you may be experiencing with joomla server overload:
1. My site loads too slowly
2.It gives you an error page when it loads
3. I'm regularly switched off by my host and i have been asked to turn on my cache before my site would be put back online
4. My site loads into a white dis organized page (first check that you are not importing articles from a microsoft word)
5. I have been warned by my host that my site is using too much resources.
1. I would recommend that you get rid of some un-necessary modules you dont need and delete them entirely from the site and server as these may be calling up some database queries even if they are disabled ( A case of bad programming).
2. Another thing is to go to your hosting provider and check if you need to move to a bigger server space either a VPS or Dedicated server, i know most hosting companies would like to push you to do this but make sure you are seeking the best advice. Check your Bandwidth limit used up monthly and your remaining disk space and then determine if you will really heed their advice and try to get a second and third opinion from an expert in the related field, you can do this by simply visiting hosting forums online and asking questions. Most forum members are usually very helpful and would offer you the best and truthful advice they can give.
3. If your case is the case where you are using up too much resources, please take note, if you are on a shared hosting or VPS, please tell your hosting provider to help you delete your trash bin, usually you would not have access to this trash bin , you may think you have deleted all your trash from cpanel admin but really that is not the case. A helpful hosting admin was able to dig around the problem and found that my client had 18 GB worth of trash not deleted. Once this was done, the site's speed was up again and there was little issue with resource. so it is really advisable to let your host make sure all the trash has been deleted.
Thanks and watch out for more update.