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Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
Caching and tuning fun for high scalability @ FrOSCon 2011
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Caching and tuning fun for high scalability @ FrOSCon 2011

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"Caching and tuning fun for high scalability" talk at FrOSCon 2011 …

"Caching and tuning fun for high scalability" talk at FrOSCon 2011

Twitter : @wimgtr

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  • 1. Caching and tuning fun for high scalability Wim Godden Cu.be Solutions
  • 2. Notes about this presentation <ul>This presentation was part of the FrOSCon 2011 program. It was designed to presented live and as a result many of the slides may seem odd without spoken explanation. The live benchmarks at the conference are ofcourse also not part of these slides. </ul>
  • 3. Who am I ? <ul><li>Wim Godden (@wimgtr)
  • 4. Owner of Cu.be Solutions (http://cu.be)
  • 5. PHP developer since 1997
  • 6. Developer of OpenX
  • 7. Zend Certified Engineer
  • 8. Zend Framework Certified Engineer
  • 9. MySQL Certified Developer </li></ul>
  • 10. Who are you ? <ul><li>Developers ?
  • 11. System/network engineers ?
  • 12. Managers ?
  • 13. Caching experience ? </li></ul>
  • 14. Caching and tuning fun for high scalability Wim Godden Cu.be Solutions
  • 15. Goals of this tutorial <ul><li>Everything about caching and tuning
  • 16. A few techniques </li><ul><li>How-to
  • 17. How-NOT-to </li></ul><li>-> Increase reliability, performance and scalability
  • 18. 5 visitors/day -> 5 million visitors/day
  • 19. (Don't expect miracle cure !) </li></ul>
  • 20. LAMP
  • 21. LAMP
  • 22. Architecture
  • 23. Our test site
  • 24. Our base benchmark <ul><li>Apachebench = useful enough
  • 25. Result ? </li></ul>
  • 26. Caching
  • 27. What is caching ?
  • 28. What is caching ? select * from article join user on article.user_id = user.id order by created desc limit 10
  • 29. Caching goals <ul><li>Source of information (db, file, webservice, …) : </li><ul><li>Reduce # of request
  • 30. Reduce the load </li></ul><li>Latency : </li><ul><li>Reduce for visitor
  • 31. Reduce for Webserver load </li></ul><li>Network : </li><ul><li>Send less data to visitor
  • 32. Hey, that's frontend ! </li></ul></ul>
  • 33. Theory of caching DB
  • 34. Theory of caching DB
  • 35. Theory of caching if ($data == false) DB
  • 36. Caching techniques <ul>#1 : Store entire pages <li>Company Websites
  • 37. Blogs
  • 38. Full pages that don't change
  • 39. Render -> Store in cache -> retrieve from cache </li></ul>
  • 40. Caching techniques <ul>#1 : Store entire pages </ul>
  • 41. Caching techniques <ul>#2 : Store parts of a page <li>Most common technique
  • 42. Usually a small block in a page
  • 43. Best effect : reused on lots of pages </li></ul>
  • 44. Caching techniques <ul>#2 : Store parts of a page </ul>
  • 45. Caching techniques <ul>#3 : Store SQL queries <li>↔ SQL query cache </li><ul><ul><li>Limited in size </li></ul></ul></ul>
  • 46. Caching techniques <ul>#3 : Store SQL queries <li>↔ SQL query cache </li><ul><ul><li>Limited in size
  • 47. Resets on every insert/update/delete
  • 48. Server and connection overhead </li></ul></ul><li>Goal : </li><ul><li>not to get rid of DB
  • 49. free up DB resources for more hits ! </li></ul></ul>
  • 50. Caching techniques <ul>#3 : Store SQL queries </ul>
  • 51. Caching techniques <ul>#4 : Store complex processing results <li>Not just calculations
  • 52. CPU intensive tasks : </li><ul><li>Config file parsing
  • 53. XML file parsing
  • 54. Loading CSV in an array </li></ul><li>Save resources -> more resources available </li></ul>
  • 55. Caching techniques <ul>#4 : Store complex processing results </ul>
  • 56. Caching techniques <ul>#xx : Your call Only limited by your imagination ! When you have data, think : <li>Creating time ?
  • 57. Modification frequency ?
  • 58. Retrieval frequency ? </li></ul>
  • 59. How to find cacheable data <ul><li>New projects : start from 'cache everything'
  • 60. Existing projects : </li><ul><li>Look at MySQL slow query log
  • 61. Make a complete query log (don't forget to turn it off !)
  • 62. Check page loading times </li></ul></ul>
  • 63. Caching storage - MySQL query cache <ul><li>Use it
  • 64. Don't rely on it
  • 65. Good if you have : </li><ul><li>lots of reads
  • 66. few different queries </li></ul><li>Bad if you have : </li><ul><li>lots of insert/update/delete
  • 67. lots of different queries </li></ul></ul>
  • 68. Caching storage - Disk <ul><li>Data with few updates : good
  • 69. Caching SQL queries : preferably not
  • 70. DON'T use NFS or other network file systems </li><ul><li>especially for sessions
  • 71. high latency
  • 72. locking issues ! </li></ul></ul>
  • 73. Caching storage - Disk / ramdisk <ul><li>Overhead : filesystem access
  • 74. Limited number of files per directory </li><ul><li>-> Subdirectories </li></ul><li>Local </li><ul><li>5 Webservers -> 5 local caches
  • 75. -> Hard to scale
  • 76. How will you keep them synchronized ? </li><ul><li>-> Don't say NFS or rsync ! </li></ul></ul></ul>
  • 77. Caching storage - Memcache <ul><li>Facebook, Twitter, Slashdot, … -> need we say more ?
  • 78. Distributed memory caching system
  • 79. Multiple machines ↔ 1 big memory-based hash-table
  • 80. Key-value storage system </li><ul><li>Keys - max. 250bytes
  • 81. Values - max. 1Mbyte </li></ul></ul>
  • 82. Caching storage - Memcache <ul><li>Facebook, Twitter, Slashdot, … -> need we say more ?
  • 83. Distributed memory caching system
  • 84. Multiple machines ↔ 1 big memory-based hash-table
  • 85. Key-value storage system </li><ul><li>Keys - max. 250bytes
  • 86. Values - max. 1Mbyte </li></ul><li>Extremely fast... non-blocking, UDP (!) </li></ul>
  • 87. Memcache - where to install
  • 88. Memcache - where to install
  • 89. Memcache - installation & running it <ul><li>Installation </li><ul><li>Distribution package
  • 90. PECL
  • 91. Windows : binaries </li></ul><li>Running </li><ul><li>No config-files
  • 92. memcached -d -m <mem> -l <ip> -p <port>
  • 93. ex. : memcached -d -m 2048 -l 127.0.0.1 -p 11211 </li></ul></ul>
  • 94. Caching storage - Memcache - some notes <ul><li>Not fault-tolerant </li><ul><li>It's a cache !
  • 95. Lose session data
  • 96. Lose shopping cart data
  • 97. ... </li></ul></ul>
  • 98. Caching storage - Memcache - some notes <ul><li>Not fault-tolerant </li><ul><li>It's a cache !
  • 99. Lose session data
  • 100. Lose shopping cart data
  • 101. … </li></ul><li>Different libraries </li><ul><li>Original : libmemcache
  • 102. New : libmemcached (consistent hashing, UDP, binary protocol, …) </li></ul><li>Firewall your Memcache port ! </li></ul>
  • 103. Memcache in code <?php $memcache = new Memcache(); $memcache->addServer( '172.16.0.1' , 11211); $memcache->addServer( '172.16.0.2' , 11211); $myData = $memcache->get( 'myKey' ); if ($myData === false ) { $myData = GetMyDataFromDB(); // Put it in Memcache as 'myKey', without compression, with no expiration $memcache->set( 'myKey' , $myData, false , 0); } echo $myData;
  • 104. Let's give that a go ! /** * Retrieves the 10 highest rated articles * @return array List of highest rated articles */ static public function getTopRatedArticleList () { if ($articleList = $cache->load( 'topRatedArticleList' ) === false) { $articleList = self :: getTopRatedArticleListUncached (); $cache->save($articleList, 'topRatedArticleList' ); } return $articleList; }
  • 105. Where's the data ? <ul><li>Memcache client decides (!)
  • 106. 2 hashing algorithms : </li><ul><li>Traditional </li><ul><li>Server failure -> all data must be rehashed </li></ul><li>Consistent </li><ul><li>Server failure -> 1/x of data must be rehashed (x = # of servers) </li></ul></ul><li>No replication ! </li></ul>
  • 107. Memcache slabs <ul>(or why Memcache says it's full when it's not) <li>Multiple slabs of different sizes : </li><ul><li>Slab 1 : 400 bytes
  • 108. Slab 2 : 480 bytes (400 * 1.2)
  • 109. Slab 3 : 576 bytes (480 * 1.2) (and so on...) </li></ul><li>Multiplier (1.2 here) can be configured
  • 110. Each larger slab has room for fewer items (chunks)
  • 111. -> Store a lot of very large objects
  • 112. -> Large slabs might be full
  • 113. -> Rest of slabs might be free
  • 114. -> Try to store more -> eviction of data ! </li></ul>
  • 115. Memcache - Is it working ? <ul><li>Connect to it using telnet </li><ul><li>&quot;stats&quot; command ->
  • 116. Use Cacti or other monitoring tools </li></ul></ul>STAT pid 2941 STAT uptime 10878 STAT time 1296074240 STAT version 1.4.5 STAT pointer_size 64 STAT rusage_user 20.089945 STAT rusage_system 58.499106 STAT curr_connections 16 STAT total_connections 276950 STAT connection_structures 96 STAT cmd_get 276931 STAT cmd_set 584148 STAT cmd_flush 0 STAT get_hits 211106 STAT get_misses 65825 STAT delete_misses 101 STAT delete_hits 276829 STAT incr_misses 0 STAT incr_hits 0 STAT decr_misses 0 STAT decr_hits 0 STAT cas_misses 0 STAT cas_hits 0 STAT cas_badval 0 STAT auth_cmds 0 STAT auth_errors 0 STAT bytes_read 613193860 STAT bytes_written 553991373 STAT limit_maxbytes 268435456 STAT accepting_conns 1 STAT listen_disabled_num 0 STAT threads 4 STAT conn_yields 0 STAT bytes 20418140 STAT curr_items 65826 STAT total_items 553856 STAT evictions 0 STAT reclaimed 0
  • 117. Memcache - backing up
  • 118. Memcache - deleting <?php $memcache = new Memcache(); $memcache->delete( 'myKey' ); $myData = $memcache->get( 'myKey' ); // $myData === false
  • 119. Memcache - tip <ul>Page with multiple blocks ? -> use Memcached::getMulti() Warning : what if you get some hits and some misses ? </ul>
  • 120. Naming your keys <ul><li>Key names must be unique
  • 121. Prefix / namespace your keys !
  • 122. Only letters, numbers and underscore
  • 123. md5() is useful </li><ul><li>-> BUT : harder to debug </li></ul><li>Use clear names
  • 124. Document your key names ! </li></ul>
  • 125. Updating data
  • 126. Updating data
  • 127. Adding/updating data $memcache->delete( 'ArticleDetails__Toshiba_32C100U_32_Inch' ); $memcache->delete( 'Homepage_Popular_Product_List' );
  • 128. Adding/updating data
  • 129. Adding/updating data - Why it crashed
  • 130. Adding/updating data - Why it crashed
  • 131. Adding/updating data - Why it crashed
  • 132. Cache stampeding elePHPants
  • 133. Cache stampeding
  • 134. Memcache code ? DB
  • 135. Cache warmup scripts <ul><li>Used to fill your cache when it's empty
  • 136. Run it before starting Webserver !
  • 137. 2 ways : </li><ul><li>Visit all URLs </li><ul><li>Error-prone
  • 138. Hard to maintain </li></ul><li>Call all cache-updating methods </li></ul><li>Make sure you have a warmup script ! </li></ul>
  • 139. Cache stampeding - what about locking ? <ul>Seems like a nice idea, but... <li>Lock in place
  • 140. -> lots of new connections
  • 141. -> memory spike
  • 142. What if the process that created the lock fails ? </li></ul>
  • 143. Quick word about expiration <ul><li>General rule : don't let things expire
  • 144. Exception to the rule : things that have an end date (calendar items) </li></ul>
  • 145. So... <ul>DON'T DELETE FROM CACHE (and don't expire unless usefull) </ul>
  • 146. LAMP... <ul>-> LAMMP -> LANMMP </ul>
  • 147. Nginx <ul><li>Web server
  • 148. Reverse proxy
  • 149. Lightweight, fast
  • 150. 7.5% of all Websites </li></ul>
  • 151. Nginx <ul><li>No threads, event-driven
  • 152. Uses epoll / kqueue
  • 153. Low memory footprint
  • 154. 10000 active connections = normal </li></ul>
  • 155. Nginx - a true alternative to Apache ? <ul><li>Not all Apache modules </li><ul><li>mod_auth_*
  • 156. mod_dav*
  • 157. … </li></ul><li>Basic modules are available
  • 158. Some 3 rd party modules (needs recompilation !) </li></ul>
  • 159. Nginx - Installation <ul><li>Packages
  • 160. Win32 binaries
  • 161. Build from source (./configure; make; make install) </li></ul>
  • 162. Nginx - Configuration server { listen 80; server_name www.domain.ext *.domain.ext; index index.html; root /home/domain.ext/www; } server { listen 80; server_name photo.domain.ext; index index.html; root /home/domain.ext/photo; }
  • 163. Nginx - phase 1 <ul><li>Move Apache to a different port (8080)
  • 164. Put Nginx at port 80
  • 165. Nginx serves all statics (images, css, js, …)
  • 166. Forward dynamic requests to Apache </li></ul>
  • 167. Nginx for static files only server { listen 80; server_name www.domain.ext; location ~* ^.*.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|pdf|ppt|txt|tar|rtf|js)$ { expires 30d; root /home/www.domain.ext; } location / { proxy_pass http://www.domain.ext:8080; proxy_pass_header Set-Cookie; proxy_set_header X-Real-IP $remote_addr; proxy_set_header Host $host; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; } }
  • 168. Nginx - let's give that a go !
  • 169. Nginx for PHP ? <ul>LANMMP to... LNMPP (ok, this is getting ridiculous) </ul>
  • 170. Nginx with PHP <ul><li>In the past : spawn-fcgi (from Lighttpd)
  • 171. Now : PHP-FPM (in PHP 5.3 !)
  • 172. Runs on port 9000
  • 173. Nginx connects using fastcgi method </li></ul>location / { fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; include fastcgi_params; fastcgi_param SCRIPT_NAME $fastcgi_script_name; fastcgi_param SCRIPT_FILENAME /home/www.phpbenelux.eu/$fastcgi_script_name; fastcgi_param SERVER_NAME $host; fastcgi_intercept_errors on; }
  • 174. Nginx + PHP-FPM features <ul><li>Graceful upgrade
  • 175. Spawn new processes under high load
  • 176. Chroot
  • 177. Slow request log ! </li></ul>
  • 178. Nginx + PHP-FPM features <ul><li>Graceful upgrade
  • 179. Spawn new processed under high load
  • 180. Chroot
  • 181. Slow request log !
  • 182. fastcgi_finish_request() -> offline processing </li></ul>
  • 183. Nginx + PHP-FPM - performance ?
  • 184. Reverse proxy time...
  • 185. Varnish <ul><li>Not just a load balancer
  • 186. Reverse proxy cache / http accelerator / …
  • 187. Caches (parts of) pages in memory
  • 188. Careful : </li><ul><li>uses threads
  • 189. Nginx is faster and scales better (but doesn't have VCL) </li></ul></ul>
  • 190. Varnish - Installation & configuration <ul><li>Installation </li><ul><li>Packages
  • 191. Source : ./configure && make && make install </li></ul><li>Configuration </li><ul><li>/etc/default/varnish
  • 192. /etc/varnish/*.vcl </li></ul></ul>
  • 193. Varnish - backends + load balancing backend server1 { .host = &quot;192.168.0.10&quot;; } backend server2{ .host = &quot;192.168.0.11&quot;; } director example_director round-robin { { .backend = server1; } { .backend = server2; } }
  • 194. Varnish - backends + load balancing backend server1 { .host = &quot;192.168.0.10&quot;; .probe = { .url = &quot;/&quot;; .interval = 5s; .timeout = 1 s; .window = 5; .threshold = 3; } }
  • 195. Varnish - VCL <ul><li>Varnish Configuration Language
  • 196. DSL (Domain Specific Language) </li><ul><li>-> compiled to C </li></ul><li>Hooks into each request
  • 197. Defines : </li><ul><li>Backends (web servers)
  • 198. ACLs
  • 199. Load balancing strategy </li></ul><li>Can be reloaded while running </li></ul>
  • 200. Varnish - whatever you want <ul><li>Real-time statistics (varnishtop, varnishhist, ...)
  • 201. ESI </li></ul>
  • 202. Varnish - ESI <ul>Perfect for caching pages </ul>In your article page output : <esi:include src=&quot;/latest-news&quot;/>
  • 203. Varnish with ESI - hold on tight !
  • 204. Varnish - what can/can't be cached ? <ul><li>Can : </li><ul><li>Static pages
  • 205. Images, js, css
  • 206. Pages or parts of pages that don't change often (ESI) </li></ul><li>Can't : </li><ul><li>POST requests
  • 207. Requests with Set-Cookie
  • 208. Very large files (it's not a file server !)
  • 209. User-specific content </li></ul></ul>
  • 210. ESI -> no caching on user-specific content ? Logged in as : Wim Godden 5 messages TTL = 5min TTL=1h TTL = 0s ?
  • 211. Coming to an Nginx near you soon... Logged in as : Wim Godden 5 messages <esim:include src=&quot;/news&quot; ttl=&quot;5m&quot; /> <esim:include src=&quot;/menu&quot; ttl=&quot;1h&quot; /> <esim:include src=&quot;/top&quot; usercookie=&quot;PHPSESS_ID&quot; ttl=&quot;1h&quot; />
  • 212. New message arrives... <ul><li>Hash using page name and session
  • 213. Self-chosen key (i.e. 'mails_for_' followed by session) </li></ul>DB
  • 214. Advantages <ul><li>No hits to backend anymore (except the first one) ! </li><ul><li>Not for user-specific content
  • 215. Not even for non-specific content </li></ul></ul>
  • 216. Do we need TTLs ? Logged in as : Wim Godden 5 messages <esim:include src=&quot;/news&quot; ttl=&quot;5m&quot; /> <esim:include src=&quot;/menu&quot; ttl=&quot;1h&quot; /> <esim:include src=&quot;/top&quot; usercookie=&quot;PHPSESS_ID&quot; ttl=&quot;1h&quot; />
  • 217. Advantages <ul><li>No hits to backend anymore (except the first one) ! </li><ul><li>Not for user-specific content
  • 218. Not even for non-specific content </li><ul><li>No TTLs for non-specific content
  • 219. TTL for user-specific content is required (defaults to 5min) </li></ul></ul><li>No need to specify ESI parameters in configuration file </li><ul><li>Only needs enabling </li></ul></ul>
  • 220. How many Memcache requests ? Logged in as : Wim Godden 5 messages <esim:include src=&quot;/news&quot; ttl=&quot;5m&quot; /> <esim:include src=&quot;/menu&quot; ttl=&quot;1h&quot; /> <esim:include src=&quot;/top&quot; usercookie=&quot;PHPSESS_ID&quot; ttl=&quot;1h&quot; />
  • 221. Advantages <ul><li>No hits to backend anymore (except the first one) ! </li><ul><li>Not for user-specific content
  • 222. Not even for non-specific content </li><ul><li>No TTLs for non-specific content
  • 223. TTL for user-specific content is required (defaults to 5min) </li></ul></ul><li>No need to specify ESI parameters in configuration file </li><ul><li>Only needs enabling </li></ul><li>Memcache getMulti -> 1 Memcache request per page </li></ul>
  • 224. Under development <ul><li>Feature set = unclear
  • 225. Performance = even more unclear </li><ul><li>Debugging code makes it slow </li></ul><li>Extends ESI standard, but doesn't follow it entirely </li><ul><li>(what standard ?) </li></ul><li>Release date ? </li><ul><li>End 2011 ? </li></ul></ul>
  • 226. Tuning
  • 227. Apache - tuning tips <ul><li>Disable unused modules -> fixes 10% of performance issues
  • 228. Set AllowOverride to None
  • 229. Disable SymLinksIfOwnerMatch </li><ul><li>Why ? Site in /var/www/domain.com/subdomain/html </li></ul><li>MinSpareServers, MaxSpareServers, StartServers, MaxClients, MPM selection -> a whole session of its own ;-)
  • 230. Don't mod_proxy -> use Nginx or Varnish !
  • 231. High load on an SSL-site ? -> put SSL on a reverse proxy </li></ul>
  • 232. PHP speed - some tips <ul><li>Upgrade PHP - every minor release has 5-15% speed gain !
  • 233. Use an opcode cache </li></ul>
  • 234. Caching storage - Opcode caching
  • 235. PHP speed - some tips <ul><li>Upgrade PHP - every minor release has 5-15% speed gain !
  • 236. Use an opcode cache
  • 237. Profile your code </li><ul><li>XHProf
  • 238. Xdebug </li></ul></ul>
  • 239. KCachegrind is your friend
  • 240. PHP speed - some tips <ul><li>Upgrade PHP - every minor release has 5-15% speed gain !
  • 241. Use an opcode cache
  • 242. Profile your code </li><ul><li>XHProf
  • 243. Xdebug </li></ul><li>But : turn off profilers on acceptance/production platforms !
  • 244. Let's see what difference opcode caching and profilers make... </li></ul>
  • 245. DB speed - some tips <ul><li>Avoid NOW() -> use PHP date(&quot;Y-m-d&quot;) as a parameter </li><ul><li>Why ? Query cache ! </li></ul><li>Index, index, index ! (where needed only)
  • 246. Use same types for joins </li><ul><li>i.e. don't join decimal with int </li></ul><li>RAND() is evil !
  • 247. count(*) is evil in InnoDB without a where clause ! </li><ul><li>(and there are other examples of specific things to avoid) </li></ul><li>Select the right storage engine
  • 248. Persistent connect is not always good ! </li></ul>
  • 249. Caching & Tuning @ frontend http://www.websiteoptimization.com/speed/tweak/average-web-page/
  • 250. Caching in the browser <ul><li>HTTP 304 (Not modified)
  • 251. Expires/Cache-Control header </li></ul>
  • 252. HTTP 304 First request Next requests
  • 253. HTTP 304 with ETag First request Next requests
  • 254. Expires/Cache-control header <ul>Cache-Control <ul><li>HTTP/1.1
  • 255. Seconds to expiry
  • 256. Used by browsers </li></ul></ul>First request Next requests No requests until item expires <ul>Expires <ul><li>HTTP/1.0
  • 257. Date to expire on
  • 258. Used by old proxies
  • 259. Requires clock to be accurate ! </li></ul></ul>
  • 260. Pragma: no-cache = evil <ul><li>&quot;Pragma: no cache&quot; doesn't make it uncacheable
  • 261. Don't want caching on a page ? </li><ul><li>HTTP/1.0 : &quot;Expires : Fri, 30 Oct 1998 00:00:00 GMT&quot; (in the past)
  • 262. HTTP/1.1 : &quot;Cache-Control: no-store&quot; </li></ul></ul>
  • 263. Frontend tuning <ul>1. You optimize backend 2. Frontend engineers messes up -> havoc on backend 3. Don't forget : frontend sends requests to backend ! SO... <li>Care about frontend
  • 264. Test frontend
  • 265. Check what requests frontend sends to backend </li></ul>
  • 266. Tuning frontend <ul><li>Minimize requests </li><ul><li>Combine CSS/JavaScript files
  • 267. Use inline images in CSS/XHTML (not supported on all browsers yet) </li></ul></ul>
  • 268. Frontend tuning - inline CSS/XHTML images #navbar span { width: 31px; height: 31px; display: inline; float: left; margin-right: 4px; } .home { background-image: url(data:image/gif;base64,R0lGODlhHwAfAPcAAAAAAIxKAKVjCLW1tb29tcbGvc7OxtZ7ANbWztbW1tbe1t7e1uelMefn1ufn3ufn5+fv3u+MAO/v5+/v7/fGCPf35/f37//nY////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////........MEl0nGVUC6tObNnPceSFBaQVMJAxC4lo3gNOrUaFnTHoAxNm3XVxPfRq139e8BEGAjWD5bgIALw287T8AcAXLly2kjOACdc17higXSIKDO/Lpv7Qq4bw7APgBq8eOzX69InrZ6xe3dbxZffyTGkb8tdx8F+b0Xn2sFsCSBAgTM5lp63RHYnoHUudZgRgkGOGCB+43nGk4OGcQTabKx5dyJKJ7ImoUNCaRRAZYN1ppsrT3Y2gIwyjSQBAtUpABml/0IJGYd6VjQUDH9uBFkGxGm5I8dPQaRUAQUMBdhhBV25ZYUJZBcSAtSJBddWZZ5UAGPOTXlgkNVOSZdBxEwIkYu7VhYnAol5GaadRqF0Uaz0TgXnX2umVFyGakJUUAAADs=); margin-left: 4px; } <img border=0 src=&quot;data:image/gif;base64,R0lGODlhHwAfAPcAAAAAAIxKAKVjCLW1tb29tcbGvc7OxtZ7ANbWztbW1tbe1t7e1uelMefn1ufn3ufn5+fv3u+MAO/v5+/v7/fGCPf35/f37//nY/......Uaz0TgXnX2umVFyGakJUUAAADs=&quot;>
  • 269. Tuning frontend <ul><li>Minimize requests </li><ul><li>Combine CSS/JavaScript files
  • 270. Use inline images in CSS (not supported on all browsers yet)
  • 271. Use CSS Sprites </li></ul></ul>
  • 272. CSS Sprites
  • 273. Tuning content - CSS sprites
  • 274. Tuning content - CSS sprites 11 images 11 HTTP requests 24KByte 1 images 1 HTTP requests 14KByte
  • 275. Tuning frontend <ul><li>Minimize requests </li><ul><li>Combine CSS/JavaScript files
  • 276. Use inline images in CSS (not supported on all browsers yet)
  • 277. Use CSS Sprites (horizontally if possible) </li></ul><li>Put CSS at top
  • 278. Put JavaScript at bottom </li><ul><li>Max. no connections
  • 279. Especially if JavaScript does Ajax (advertising-scripts, …) ! </li></ul><li>Avoid iFrames </li><ul><li>Again : max no. of connections </li></ul><li>Don't scale images in HTML
  • 280. Have a favicon.ico (don't 404 it !) </li></ul>
  • 281. Tuning frontend <ul><li>Use GET for Ajax retrieval requests (and cache them !)
  • 282. Split requests across subdomains
  • 283. Put statics on a separate subdomain (without cookies !) </li></ul>www.whatever.com www.whatever.com images.whatever.com
  • 284. Tuning miscellaneous <ul><li>Avoid DNS lookups </li><ul><li>Frontend : don't use too many subdomains (2 = ideal)
  • 285. Backend : </li><ul><li>Turn off DNS resolution in Apache : HostnameLookups Off
  • 286. If your app uses external data </li><ul><li>Run a local DNS cache (timeout danger !)
  • 287. Make sure you can trust DNS servers (preferable run your own) </li></ul></ul></ul><li>Compress non-binary content (GZIP) </li><ul><li>mod_deflate in Apache
  • 288. HttpGzipModule in Nginx (HttpGzipStaticModule for pre-zipped statics !)
  • 289. No native support in Varnish </li></ul></ul>
  • 290. What else can kill your site ? <ul><li>Redirect loops </li><ul><li>Multiple requests </li><ul><li>More load on Webserver
  • 291. More PHP to process </li></ul><li>Additional latency for visitor
  • 292. Try to avoid redirects anyway
  • 293. -> In ZF : use $this->_forward instead of $this->_redirect </li></ul><li>Watch your logs, but equally important...
  • 294. Watch the logging process ->
  • 295. Logging = disk I/O -> can kill your site !
  • 296. Slashdot effect </li></ul>
  • 297. Above all else... be prepared ! <ul><li>Have a monitoring system
  • 298. Use a cache abstraction layer (disk -> Memcache)
  • 299. Don't install for the worst -> prepare for the worst
  • 300. Have a test-setup
  • 301. Have fallbacks </li><ul><li>Turn off non-critical functionality </li></ul></ul>
  • 302. <ul>Questions ? </ul>
  • 303. <ul>Questions ? </ul>
  • 304. Contact <ul><li>Twitter @wimgtr
  • 305. Web http://techblog.wimgodden.be
  • 306. Slides http://www.slideshare.net/wimg
  • 307. E-mail [email_address] </li></ul>
  • 308. Please... <ul><li>Rate my talk : http://tinyurl.com/cachetune
  • 309. Vote to see me talk at Confoo : http://www.confoo.ca </li><ul><li>Caching and tuning fun for high scalability
  • 310. Keeping old code alive without non-stop hassle
  • 311. Beyond PHP : it's not (just) about the code !
  • 312. Who's in control of your PHP app ?
  • 313. Creating Fast, Dynamic ACLs in Zend Framework </li></ul></ul>
  • 314. <ul>Thanks ! </ul>
  • 315.  

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