Troubleshooting site slowness

There are a few common issues that can cause slowness to occur. This article lists the mos common causes and several suggestions to speed up your site.

Testing your site from external locations

The first thing you should do when noticing slowness is to test your site at a 3rd party website. There are several websites that provide online tools to test website performance. These help to verify if the performance issues are happening in all locations or if it’s just your connection.

If you see the slowness is occurring in all locations, proceed with the following steps to troubleshoot your site.

Databases

Most sites that run slowly are database-driven sites. Database content is not saved on the web server. Unless you have some sort of caching enabled for this site server. If no caching is enabled, content is dynamically created for each visitor by the communication between the web server and the database server.

Checking for database overhead

Your MySQL database might run slowly if it has a lot of overhead. If tables in your database have excessive "overhead" (unused empty space), it can cause queries to the database to take longer, and may result in the web server timing out before it can receive the response from the database server. 

View the following article for detailed instructions on how to optimize your database using phpMyAdmin or SSH.

Ensuring your web and database servers are in the same data center

DreamHost currently has four (4) data centers that customers can use:

  • Los Angeles, California, USA
  • Irvine, California, USA
  • Ashburn, Virginia, USA
  • Portland, Oregon, USA

To see which data center(s) your account is utilizing, visit the (Panel > 'Support' > 'Data Centers') page.

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In the above screenshot, both the website and its database are in the same data center in Virginia. This is how your panel should look (although the data center may be different).

Ideally, your web and MySQL servers should be located in the same data center to reduce any networking delays. If you visit that page and notice that these two servers are not in the same data center, contact support on the (Panel > 'Support' > 'Contact Support') page. Support is then be able to migrate your servers to the same location.

All email hosting services for email addresses (created on the Panel > 'Mail' > 'Manage Email' page) are currently hosted exclusively in the Los Angeles, CA. However, this does not affect your site performance.

 

Checking the PHP version

If your site is built on PHP, make sure you're running a supported and current version.  Newer versions of PHP run faster/smarter and can handle issues arising from increasing traffic more gracefully than older versions of PHP.

For more information about checking which version of PHP you are running, please review the following article:

It might also help to increase the amount of memory that PHP is allowed to use. You can do this yourself by modifying the “memory_limit” PHP.ini directive. View the following article for detailed instructions on how to increase this limit.

One-Click Installs

Checking the version of installed software

Web applications (like WordPress, Joomla, MediaWiki, etc.) are updated on a semi-regular basis by their core developers both to improve the application itself and to block any security issues found in a previous version. For the best performance, make sure that your installations are updated on a regular basis.

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If you have installed software using DreamHost’s One-Click Installer, then updating is easy. View the following article for full instructions:

Checking for unused plugins

If a plugin's files still exist, (even if it is set to inactive/disabled), it can still execute code and affect the performance of your site. If you cannot access the administration area of your software, you may need to log in via FTP/SFTP/SSH and remove plugins that you do not use. This may help to bring your usage down enough to allow the admin area to load. If you need help connecting to your domain via FTP/SFTP/SSH, take a look at the following articles:

View the following article for instructions on how to disable WordPress plugins:

Using caching and anti-spam plugins

In general, reducing the number of plugins that you use ensures that your install runs more efficiently. However, adding anti-spam and caching plugins can help to speed up your site.

Checking your server

It’s also possible that there may be a momentary load on your server causing slowness. View the following article that lists several commands you can run on your web server:

Checking for over-browsing by specific IPs

Usually, if there is one (or a few) IP address(es) that represent 10% or more of your site's visits (1,000 or more visits out of the last 10,000), checking the hostname of the IP address often shows that it belongs to a search engine bot, usually from Google and Yahoo. These bots are NOT responsible for your site's ranking. Occasionally, these bots attempt to browse your site hundreds of times a day, impacting your site’s performance and preventing actual visitors from reaching you.

You can find instructions on how to check which IPs viewed your site recently, and how to block them, in the following article:

Using ping and traceroute

Check the response time/connection between your computer and your DreamHost servers by running a ping and a traceroute. If you need more information about running ping or traceroute, take a look at the following articles:

If you see any issues, contact support and provide the results of these tests. Support is then able to look further into the matter for you.

See also

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