Making WordPress Fly


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Stefan Didak's presentation about APC, memcached, varnish, and other tools for speeding up your WordPress site (as long as you're in charge of your own server). From the October 2013 East Bay WordPress Meetup.

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Making WordPress Fly

  3. 3. Stefan Didak (“not a web developer”) Sunday, October 6, 13
  4. 4. The sound a WordPress site should make when your client is happy to pay you more because their site is so fast that it puts their competition to shame. TIME = MONEY Sunday, October 6, 13
  5. 5. Caching provided by optimizing your site Caching through plugins Caching because of all of the above As you’ve already been shown today LEVELS OF CACHING all of those make a difference but... NOT ENOUGH Sunday, October 6, 13
  6. 6. Don’t just optimize your site Optimize YOUR SERVER! and if you have none, build one! Optimize YOUR CODE TOO! LEVELS OF CACHING Everything I’m going to show today requires you to have full control and access to your server (VM, VPS, Cloud, etc.) Sunday, October 6, 13
  7. 7. WordPress Caching Digital Ocean + DEMO OpCode Caching Apache v.s. Nginx Varnish Memcached WHAT I’LL BE COVERING Also known as the Tip of the Iceberg Sunday, October 6, 13
  8. 8. WP CACHING OVERVIEW Everyone should know what levels of caching WP supports Sunday, October 6, 13
  9. 9. Only lasts the duration of the request. After the request the run-time cache no longer exists. For example: the global $post and $wp_query variables WORDPRESS CACHING Run-Time Cache Sunday, October 6, 13
  10. 10. WordPress has a “Transient Cache” API that allows you to store data in your MySQL DB. Ahum... Right... But it can still be useful... if used selectively WORDPRESS CACHING Transient Cache Sunday, October 6, 13
  11. 11. Is usually persistent because it’s stored “somewhere”. Somewhere could be in memory through APC, Memcached, or Redis, but could also be in your MySQL DB or on disk. WORDPRESS CACHING Object Cache Sunday, October 6, 13
  12. 12. Stores HTML data representing entire pages. This is one of the more typical caching schemes used by most plugins. Unfortunately, not so useful when you have highly dynamic pages where someone does not always get the same content (i.e. membership sites). WORDPRESS CACHING Page Cache - Stored on disk or in memory Sunday, October 6, 13
  13. 13. I don’t like the term and it is no different from the Object Cache. Instead of storing entire HTML pages it stores parts of pages. I like to think of it as just another object because that’s what it is. WORDPRESS CACHING Fragment Cache Sunday, October 6, 13
  14. 14. I prefer to have full control over my own online servers because I can have them be faster than managed hosting at a fraction of the cost. PERSONAL EXPERIENCE Managed Hosting, however optimized, is still designed to be a version of a “one size fits all” approach Sunday, October 6, 13
  16. 16. After running and testing my first “droplet” on Digital Ocean and after playing with some deployments on Linode I knew my shared hosting for 30+ domains would come to an end. A very WELCOME END! FIRST DEPLOYMENT It was really exciting to see my first droplet come online Sunday, October 6, 13
  17. 17. If you don’t care much about the “managed” part of managed hosting and really want things to roar like a bat out of hell... HOSTING, BUT WHERE The long search has come to an end Sunday, October 6, 13
  18. 18. Once my “stealth project” goes live I expect that within 2 years I will need around 150 to 500 virtual servers. (virtual servers of various capacities) Digital Ocean has the absolute best price point I’ve seen. And I’ve been looking. Really looking. STEALTH PROJECT Not to mention, Digital Ocean has a nice evolving API to manage all your “droplets”. Not as mature as Linode, though! Sunday, October 6, 13
  19. 19. $20/mo shared hosting v.s. $5/mo Digital Ocean Droplet Oakley Chamber of Commerce WordPress site (a heavy and NOT OPTIMIZED one!) DEMO TIME ! DEMO TIME ! If this doesn’t convince you I don’t know what will Sunday, October 6, 13
  20. 20. TRY IT FOR YOURSELF anyone with laptops here are encouraged to check it out Sunday, October 6, 13
  21. 21. WAS THAT FAST OR WAS THAT FAST? Or is it just cool to know that you can do it TOO!? YES YOU CAN Stop whining about the commandline and typing on the keyboard, as if you don’t do that crap when you’re CSS’ing!!! Sunday, October 6, 13
  22. 22. I can’t show you managed hosting vs. Digital Ocean at a $25-30/month vs. $5-10/ month price point... BUT.... Sunday, October 6, 13
  23. 23. I will take any bet, for any amount of serious money, that I can setup and configure servers on Digital Ocean or Linode that beat the living daylights out of any managed hosting in terms of performance. And YOU can do it TOO! So let’s not even talk about shared hosting anymore, ok? Sunday, October 6, 13
  24. 24. I know what I’m doing and... may be biased. I do, however, believe, that if you put in some time to learn more than what you copy & paste will serve you to be even more valuable to your clients! COPY AND PASTE If you can’t do copy and paste then I’m wasting your time and I am very sorry. If you can, however... new doors will open! Sunday, October 6, 13
  25. 25. TUTORIALS, GUIDES, AND MORE INSTALLING AND RUNNING On how to install, configure, and run with all the things I mentioned today, visit the libraries. Sunday, October 6, 13
  26. 26. OPCODE CACHING And now to explain what you’ve just seen Sunday, October 6, 13
  27. 27. What your server does for EVERY page hit on your site: Read most (or all) of your PHP files/code Interpret each line & “compile” it into what the CPU understands Execute the “compiled” code and render out the page by sending it to the browser. OPCODE CACHING Yeah, uh, sure, what what does it DO?! Sunday, October 6, 13
  28. 28. What your server does for EVERY page hit on your site: Read most (or all) of your PHP files/code Interpret each line & “compile” it into what the CPU understands Execute the “compiled” code and render out the page by sending it to the browser. OPCODE CACHING Yeah, uh, sure, what what does it DO?! Sunday, October 6, 13
  30. 30. APC XCache eAccelerator Zend OpCache NuSphere PHPExpress IonCube Accelerator OPCODE CACHING Speeds up your site much more than “regular” file/data caching Sunday, October 6, 13
  31. 31. Because APC is going to be included in “PHP6” But as we all know, there is no such thing as PHP6, right? There is a book on PHP6. But there is no Beta of PHP6. There isn’t even an Alpha of PHP6. BUT PHP 5.5 HAS OPCACHE Performance between APC, XCache, etc. is all very similar Sunday, October 6, 13
  32. 32. PHP APC APC = Alternative PHP Cache Sunday, October 6, 13
  33. 33. Without APC With “vanilla” APC Req. Per Sec : 85 Time Per Req. : 900ms Conc. Time Per Req. : 20ms Xfer Rate : 898 Kbytes/s Req. Per Sec : 138.5 Time Per Req. : 476ms Conc. Time Per Req. : 9.5ms Xfer Rate : 1265 Kbytes/s Great, but... IS THAT ALL? BENCHMARKING APC Your site without APC sucks donkey balls Sunday, October 6, 13
  34. 34. Without APC With “vanilla” APC Req. Per Sec : 85 Time Per Req. : 900ms Conc. Time Per Req. : 20ms Xfer Rate : 898 Kbytes/s Req. Per Sec : 138.5 Time Per Req. : 476ms Conc. Time Per Req. : 9.5ms Xfer Rate : 1265 Kbytes/s Now with apc.stat=off Req. Per Sec : 317.4 Time Per Req. : 152.1ms Conc. Time Per Req. : 3.1ms Xfer Rate : 3985 Kbytes/s BENCHMARKING APC Your site with APC and apc.stat = off WILL FLY! Sunday, October 6, 13
  35. 35. Only turn APC.STAT to OFF if: Your PHP code on the server does not change and you are willing to restart the web server if it does. WP or Plugin updates = CHANGE OF PHP CODE APC.STAT = OFF THINK AND PLAN BEFORE YOU TURN IT OFF Sunday, October 6, 13
  36. 36. # /etc/init.d/apache2 restart It’s just one line. Maybe not exactly the same as this one, though. And it’s only for a few seconds. RESTARTING? SO WHAT? There are other ways to deal with this but those are for another time when we get real deep into server stuff Sunday, October 6, 13
  37. 37. Ensure your server has: php-pear, php5-dev, make, apache2-prefork-dev # pecl install apc Then add the extension to your php.ini (or other) INSTALLING APC Because it might be different for your flavor of server I’m not going into too much detail here, but it’s dead easy Sunday, October 6, 13
  38. 38. apc.enabled=1 apc.shm_segments=1 apc.shm_size=128M (or 1G, etc.) apc.ttl=3600 apc.user_ttl=7200 apc.gc_ttl=3600 apc.max_file_size=1M apc.stat=1 (or 0) CONFIGURING APC You should tweak it as much as needed And there’s a lot more you can tweak in APC Sunday, October 6, 13
  39. 39. With APC installed you can use PHP function calls to... Manage the APC cache Interrogate the APC cache Load/Dump Binary cache data START OPTIMIZING YOUR CODE Integrate it selectively in your plugins WORTH KNOWING APC will also extend PHP with new functions Sunday, October 6, 13
  40. 40. APC Object Cache Backend Place the object-cache.php in your wp-content directory. Optionally you can also install the BATCACHE plugin APC WITH A WP PLUGIN Your mileage may vary Sunday, October 6, 13
  41. 41. Apache = Process Based Nginx = Event Based APACHE V.S. NGINX Because you might get a lot of visitors... all at the same time! Sunday, October 6, 13
  42. 42. Asynchronous Asynchronous = Scalability Fewer Server Resources (i.e. much less memory) Better for heavy load sites A FEW ADVANTAGES On sites with light traffic you will not see much difference in performance between event vs. processed based servers Sunday, October 6, 13
  43. 43. 10.000 concurrent connections and Nginx still uses only a few MB of memory Apache... 100’s of MB’s And often will not even handle the load. ALSO A COST DIFFERENCE Part of the cost of virtual servers is the amount of memory that is available. Disk space is not as important as memory. Sunday, October 6, 13
  44. 44. Back in 2008... 8000 live traffic requests per second Apache would have fallen over and DIED WORDPRESS.COM Big servers and big sites prefer Nginx... and now you know why Sunday, October 6, 13
  45. 45. 15MB of RAM and 10% of CPU resources Apache and a pound load balancer would freak out at the 1000th process, using 400+MB RAM and “leaking” 20MB RAM per hour GAME OVER Big servers and big sites prefer Nginx... and now you know why Sunday, October 6, 13
  46. 46. WP development is “intertwined” with the Apache world. Support is “limited but growing”. WORDPRESS & NGINX Not quite a match made in heaven You’ll have to do some marriage counseling Sunday, October 6, 13
  47. 47. Nginx has no conceptual notion of this thing called an .htaccess file Search for Nginx related WP plugins WORDPRESS & NGINX WHERE THE HECK DID MY .HTACCESS FILE GO?! Sunday, October 6, 13
  48. 48. Caching HTTP Reverse Proxy Proxy Servers are not just “the thing you set in your browser” Sunday, October 6, 13
  49. 49. BROWSER BROWSER PROXY SERVER VARNISH WEBSITE WEBSITE With Varnish YOU control the caching (because not everyone uses a proxy) VARNISH And it really is... really really, really, REALLY FAST! Sunday, October 6, 13
  50. 50. Cache on Disk Cache in Memory Control through VCL (Varnish Cache Language) VARNISH You control the proxy and you control the resources Sunday, October 6, 13
  51. 51. VARNISH PORT 80 APACHE OR NGINX PORT 8080 Varnish points to a “backend” server which happens to be itself but with the web server on a different port VARNISH SAME SERVER Change the web server port to something else because Varnish should respond on port 80 Sunday, October 6, 13
  52. 52. VARNISH PORT 80 APACHE OR NGINX PORT 8080 APACHE OR NGINX PORT 8081 VARNISH DIFFERENT SERVERS You can do the setup in whatever way you like Sunday, October 6, 13
  53. 53. # Drop any cookies sent to Wordpress. sub vcl_recv { ! if (!(req.url ~ "wp-(login|admin)")) { ! ! unset req.http.cookie; ! } } # Drop any cookies Wordpress # tries to send back to the client. sub vcl_fetch { ! if (!(req.url ~ "wp-(login|admin)")) { ! ! unset beresp.http.set-cookie; ! } } WP AND VARNISH BEWARE OF COOKIES Sunday, October 6, 13
  54. 54. MEMCACHED The name of the game is “DISTRIBUTED” Sunday, October 6, 13
  55. 55. The “for dummies” version: Make better use of memory Cache data in memory on other servers that aren’t using it as much. AND IT DOES WHAT? It manages cache and memory... for more than one server Sunday, October 6, 13
  56. 56. DISTRIBUTED, I SAID The more the merrier Sunday, October 6, 13
  57. 57. System interconnects on servers (depending on how you plan and set them up) can still get more performance over TCP/IP and memory than a local server faced with only its limited resources. More servers = more memcached WORDPRESS.COM Yes, uses memcached. As do Twitter, Flickr, Wikipedia, Craigslist, YouTube, and many others Sunday, October 6, 13
  58. 58. $mc = new Memcache; $mc->connect(‘’, 11211); $data = “cache this!”; $mc->set(‘mydata’, $data, false, 100); $result = $mc->get(‘mydata’); MEMCACHED PHP When installed Memcached will provide you a lot of PHP functionality to have full control over your caching Sunday, October 6, 13
  59. 59. BATCACHE Place the advanced-cache.php in your wp-content directory “MEMCACHED PLUGIN” Your mileage may vary Sunday, October 6, 13
  60. 60. Single Malt Scotch Hi Stefan! Bourbon Hi Mitch! Tequila Hi Kelly! Beer Hi Andrei! LIFE IN THE SLOW LANE If all this server and site performance is getting to you! :-) Sunday, October 6, 13
  61. 61. DOWNLOAD THE SLIDES Because this MAY have gone WAY too FAST for you! Sunday, October 6, 13
  62. 62. Digital Ocean Redis Linode Memcached Rackspace WordPress Batcache Amazon VPC WordPress APC Object Backend APC XCache And finally, a “real developer’s” home office because everyone keeps asking... :-) eAccelerator Zend OpCache/Optimizer/Platform Nginx Varnish THINGS MENTIONED In case you want to go look stuff up for yourself Sunday, October 6, 13
  63. 63. QUESTIONS Because I’m sure there’ll be some! Sunday, October 6, 13