Apache web servers have a module called mod_deflate. This module, when called by a website, serves to compress files sent by the server. To engage this module, insert the following code into the .htaccess file located in the root directory of your Magento installation, replacing what is currently there for the mod_deflate directive:

<IfModule mod_deflate.c>
############################################
## enable apache served files compression
## http://developer.yahoo.com/performance/rules.html#gzip

# Insert filter
SetOutputFilter DEFLATE
# Netscape 4.x has some problems...
BrowserMatch ^Mozilla/4 gzip-only-text/html
# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4\.0[678] no-gzip
# MSIE masquerades as Netscape, but it is fine
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
# Don't compress images
SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary
# Make sure proxies don't deliver the wrong content
Header append Vary User-Agent env=!dont-vary

</IfModule >

Using BrowserMob (http://www.browsermob.com) as our testing source, a configurable product page on our test site (the one we built to use for writing this book) was reduced in size from 452 KB to 124KB, a 73% reduction in the amount of data delivered!

Another Apache module, mod_expires, controls how browser caches should treat files they store on users' computers. When you visit a website, your browser caches the results. For files that have not changed since a previous visit, the browser will use the file in the cache on the local computer rather than pull it again from the web server.

The expiration of these cached files can be controlled by your web server. If your server provides no expiration instructions, then your site visitor's browser may assume that the cached information is not good (or is still good long after it is) and fail to pull the best information from your site.

Insert the following within the <IfModule mod_expires.c> directive in your root .htaccess file:

ExpiresActive On
ExpiresDefault "access plus 1 month"

You can also use a shorter period of time, but generally, you want to allow browsers to use unchanged, cached files for quite a while, thereby lessening the load on your server.

This is one of the more difficult items to change if you're hosting on a shared account, as many hosting providers will not allow you to increase the amount of memory allocated to PHP. The normal default of 64 MB may be sufficient, but if you're expecting a high volume of users, increasing this to 256 MB has produced noticeable improvements for us.

To increase this in your .htaccess file, simply place a hash mark (#) before php_value memory_limit 64M and remove the hash mark before php_value memory_limit 256M.

This is one configuration you may have trouble implementing as it involves changing a couple of core variables for MySQL. When we started looking more closely at ways of speeding up database lookups, we found that with our hosting provider, MySQL was configured to do lookups without a cache: the query cache and query cache limit were both set to zero.

By doing some research, we found that MySQL queries could be made faster by increasing the total size of the query cache and the query cache limit allowed for any one query. Other developers who had experimented with this suggested at least a limit of 1 MB for the individual query and a total limit of 64 MB would handle most initial, growing Magento stores. As your store grows, you may want to increase these limits to allow MySQL to take advantage of its own internal caching mechanism.

If you do have the ability to modify your MySQL database — or if you can request a modification with your hosting provider — you should set the query_cache_limit and the query_cache_size to amounts such as the ones given above.

Nginx is an alternative to Apache when running Magento. Significant performance improvement out of the box is driving quite a bit of this adoption, and a large number of vendors have made the switch from Apache to Nginx. In recognition of this, Magento 2 has been built with full support for Nginx. It's beyond the scope of this chapter to discuss Nginx configuration, but a vast majority of hosting providers will install Nginx for you to use. Magento 2 also has a suggested Nginx configuration file in the root folder, which can be seen via GitHub as well, here: https://github.com/magento/magento2/blob/develop/nginx.conf.sample.

Magento 2 supports Varnish and allows for general parameter and VCL (Varnish Configuration Language) management. It's beyond the scope of this book to dive into configuring a Varnish proxy on your server, but again, this is something that many Magento specific hosting providers will support and configure on your behalf. Once this is in place, you can manage Varnish through Magento 2 in the Store | Configuration | Advanced | System | Full page cache, as shown in the following screenshot:

CDNs (Content Delivery Networks), are servers which host your static or non-dynamic content on very fast servers and networks. For instance, if your images and JavaScript files are hosted on CDN servers, such as the ones provided by Amazon or Rackspace, your Magento server doesn't have to spend time processing and delivering those files to your visitors. Since web servers have limits in terms of the number of active connections they can support for delivering files, allowing other servers to carry part of the load means your server can accommodate more visitor requests.

Magento 2 has native CDN support, and if you navigate to Store | Configuration | Web you'll see an area called Base URLs. You can provide the CDN URL's here and Magento will automatically pull the resources from it.