There are plenty of posts showing ways to speed up Magento, and this is yet another one, but we’ll try to come up with some original techniques that hopefully will help you to improve the performance of your store.

It’s worth mentioning that all the below tips have been tested thoroughly, and we are currently taking advantage of them on many production websites. Today, we’ll focus on how we did it for our motorbikes shop.

The infrastructure where store is currently running is a skinny micro-instance with 0.6GB of RAM, shared CPU, and 10GB of hard disk. We’ve been constantly tunning all the settings trying to get the best performance out of it, and here you have the major changes that made a difference:

1. Cache:
   1. Start using FPC (Full Page Cache) if you aren’t already, this is definitely the most important thing and should be your priority. We recommend Varnish + Turpentine even though it might not be the easiest to install & configure, depending on the amount of customizations of your store. Having FPC is essential to be able to scale and handle multiple simultaneous requests, specially important in a machine where you’ve a very limited amount of RAM and CPU.
   2. Start using the PHP extension APC (or OPCACHE + APCU) and use APC for the Magento config cache (you can enable it on the local.xml). This will definitely increase the speed of your site for the non-fpc-cached pages.
2. Memcached for sessions: Many other people use Redis, and that might be even better, but as long as you don’t use files or database, you are doing just fine. You can change this setting in your local.xml. If you don’t use it for anything else, you don’t need more than 16/32MB until you have a serious amount of users.
3. Robots.txt & Blocking bots: When you start running a new website, (I completely made up that number) probably around 90% of your traffic is just bots, and even when you grow, it will still represent a very high amount of the number of requests of your site. Therefore our advise is to spend some time carefully tunning your robots.txt to prevent bots from crawling pages or images or whatever you don’t want to be crawled. Moreover, there are just too many bots out there and unless you are really interested in them all to crawl your site, my advise is to block them either by the robots.txt or by any other mechanism, such as nginx/apache config by looking at the user agent. Depending on how aggressive you are willing to be against unwanted bots, you can drastically reduce the number of requests of your server and save all those resources to delivery a much better user experience (aka speed) to your actual customers.
4. Reindex optimizations: This is one of the most painful tasks, and it can only get worse as your catalog of products increase. A good start is usually installing this url reindexer patch extension, which basically skips the disabled or not visible products from the catalog url reindex. This has proven to reduce the reindex time from nearly an hour to just a few minutes, but it will depend a lot on your catalog of products.
5. MySQL tunning: A proper configuration of your mysql instance can have a huge impact on your site’s performance. Give mysqltunner a go, it will most likely give you useful advise, but once again, it all depends on each custom setup. One setting that works well for one store, might not work for another one. Always monitor your config changes and if something doesn’t work, revert the changes.
6. Varnish/Turpentine tunning: After installing and configuring varnish+turpentine, we noticed a boost in the capacity and performance of the site, but we noticed as well that, due the CSRF protection (aka formkeys) added in the latest versions of Magento, Turpentine’s FPC stopped working as it used to do. Now, the default config will never serve a cached page to a new user, as it has to be processed by Magento in order to generate a valid session and be able to get a valid formkey through an ESI. This is a very good solution to preserve the FPC functionality and the CSRF protection, but has the downside of always giving a non-cached page to the first time visitors, which if it’s not quick enough, can make de difference between bouncing or not. Therefore, we recommend enabling the setting “Use VCL Fix” in Turpentine, but that would imply disabling the CSRF protection as well, which you should do at your own risk. Be very careful doing this as this can potentially break the add to cart and login in your store. Please, note that after enabling that setting you might still notice that the first time visitor still gets served a non-cached page, if thats the case, check this pull request and make sure you have those changes in your VLC file.
7. CDN: This one is pretty obvious, but somehow many people have the impression that having a CND is very complex and/or costly. We’ve tried a few of them and the best one we’ve found so far is KeyCDN (register through this link and you’ll get 10$ credit month trial!), mostly because of the price, but also because of the performance and the features.

Conclusion: The above list is a small subset of the many ways to speed up Magento, and it should be just the beginning of all the things that you should do in order to make your store quicker and better. There is an endless list of things that you can try, but this list highlights the changes that had a bigger impact in our micro-instance, and hopefully will be useful for not only low resource machines, but also for the majority of the Magento store setups.

If you have any questions and/or need any help, do not hesitate to get in touch.