Network problems:
1) Is it for everyone or just my local area?
Sometimes a website loads slowly not because the server is slow but because your network connection to the server is slow or intermittent at one of the network "hops" between your location and the server. The problem may not even be with your local Internet Service Provider. There are usually 5-20 different Internet Service Providers between your local computer and the server.
One of the best ways to test for network problems is to run a traceroute from your computer to the server. A traceroute will show all of the network hops between you and the server, and how long your connection took to go through each one. It will also show network timeouts (with ***). Run the following command from your computer's command prompt:
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tracert example.com
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* replace example.com with your domain name
2) Another quick and easy test for network problems is to use a proxy server to load your web page. A proxy server loads your website from a third-party location and should hopefully bypass local network problems. Example proxy servers:
http://freeproxyserver.net/
http://proxify.com/
If the site loads normally through the proxy server, but slowly for you, you've identified a network problem.
Note that proxy servers will load your site a bit more slowly than normal
3) What to do if you've identified a network problem:
If you haven't already, run a traceroute. If the timeout occurs right away, check your local network and router. If it occurs at your local Internet Service Provider or later down the line, you should contact your Internet Service Provider.
* You also have the option to simply wait out the problem. Most Internet Service Providers will have their connection up and running again within a few hours.
Page / Site specific problems
You should also test whether the slowness is limited to specific web pages, or is universal for all pages on the server. Many modern web pages contain dozens of complex elements which drag down the overall load time of the web page, and would do the same no matter how powerful or fast the host server.
Your first speed test page should be plain HTML.
Filename: test.html
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Did this page load in few seconds?
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What to do if you've narrowed the slowness to a specific page ?
To identify which elements are slowing down your web page, you should use some additional diagnostic tools to break down your page load into individual items. Firebug and Pingdom are both great tools for this
Database problems
Does your page incorporate any database queries? Most Content Management Systems (CMS's) like WordPress, Drupal, and Joomla make extensive use of the database to generate all website pages.
What to do if you've identified a problem with database requests made by your page ?
It's quite possible for a single query to take several seconds to complete, if it's written inefficiently. Add three or four of these poorly-written queries to your page, and it will load very slowly. If your speed test indicates that there are no overall database server problems, you will need to look into the individual queries that are being executed when your page loads.
** Also, investigate any plugins you are using which make complicated or inefficient database queries and consider updating or removing them.
Due to the shared nature of the Service, you may occasionally experience brief periods of resource unavailability due to high load on the server and it is common for all shared hosts on the net. However we use Cloud Linux on servers to better resource management. Also cloud linux allocate resource limit for each cpanel accounts, and If your cpanel account hit the maximum resource limit, then you can experience interruption to load your site / connect your site
More Readings >> http://secure.webhost.lk/knowledgebase/119/I-failed-to-see-my-site-for-shot-period-of-time-.html
