Nginx and friends - putting a turbo button on your site
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The document discusses various caching technologies, primarily focusing on memcache and nginx, to enhance website performance. It outlines the installation, functionality, and implementation strategies for caching, along with potential pitfalls like cache stampeding. The importance of efficient caching in reducing server load and improving response times is emphasized through examples and benchmarks.
![Memcache in code
Initialization :
MemcachedClient.Setup("MyCache", new string[]{ "server1.example.com", "server2.example.com"});
Usage :
MemcachedClient cache = MemcachedClient.GetInstance("MyCache");
string myData = cache.Get("myKey") as string;
if (myData == null) { Miss
myData = GetMyDataFromDB();
cache.Set("myKey", myData);
}
// Use myData](https://image.slidesharecdn.com/nginxandfriends-120524085300-phpapp02/85/Nginx-and-friends-putting-a-turbo-button-on-your-site-13-320.jpg)
Nginx and friends - putting a turbo button on your site
- 1. Nginx and friends aka 'Adding a turbo button to your site' Wim Godden Cu.be Solutions
- 2. Who am I ? Wim Godden (@wimgtr) Owner of Cu.be Solutions (http://cu.be) Open source developer since 1997 Developer of OpenX Zend Certified Engineer Zend Framework Certified Engineer MySQL Certified Developer
- 3. Who are you ? Developers ? System/network engineers ? Managers ?
- 5. What's outside the box ? Operating systems ? Database servers ? Webservers ? Reverse proxies ?
- 6. Website X Header Latest news Article content page Navigation Article content
- 7. What is caching ? x = 5, y = 2 Same result n = 50 CACHE select * from article join user Doesn't change on article.user_id = user.id all the time order by created desc limit 10
- 8. Caching storage - Memcache(d) Facebook, Twitter, YouTube, … → need we say more ? Distributed memory caching system Multiple machines ↔ 1 big memory-based hash-table Key-value storage system Keys - max. 250bytes Values - max. 1Mbyte
- 9. Caching storage - Memcache(d) Facebook, Twitter, YouTube, … → need we say more ? Distributed memory caching system Key-value storage system Keys - max. 250bytes Values - max. 1Mbyte Extremely fast... non-blocking, UDP (!)
- 10. Memcache - installation & running it Installation Distribution package PECL Windows : binaries Running No config-files memcached -d -m <mem> -l <ip> -p <port> ex. : memcached -d -m 2048 -l 172.16.1.91 -p 11211
- 11. Caching storage - Memcache - some notes Not fault-tolerant It's a cache ! Lose session data Lose shopping cart data ...
- 12. Caching storage - Memcache - some notes Not fault-tolerant It's a cache ! Lose session data Lose shopping cart data … Firewall your Memcache port !
- 13. Memcache in code Initialization : MemcachedClient.Setup("MyCache", new string[]{ "server1.example.com", "server2.example.com"}); Usage : MemcachedClient cache = MemcachedClient.GetInstance("MyCache"); string myData = cache.Get("myKey") as string; if (myData == null) { Miss myData = GetMyDataFromDB(); cache.Set("myKey", myData); } // Use myData
- 14. Memcache slabs (or why Memcache says it's full when it's not) Multiple slabs of different sizes : Slab 1 : 400 bytes Slab 2 : 480 bytes (400 * 1.2) Slab 3 : 576 bytes (480 * 1.2) (and so on...) Multiplier (1.2 here) can be configured Store a lot of very large objects → Large slabs : full → Rest : free → Eviction of data !
- 15. Memcache - Is it working ? Connect to it using telnet STAT pid 2941 STAT uptime 10878 STAT time 1296074240 "stats" command → STAT version 1.4.5 STAT pointer_size 64 STAT rusage_user 20.089945 Use Cacti or other monitoring tools 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
- 16. Website X – news is changing ! Header Latest news Article content page Navigation Article content
- 18. Updating data
- 19. Updating data LCD_Popular_Product_List
- 22. Adding/updating data - Why it crashed
- 23. Adding/updating data - Why it crashed
- 24. Adding/updating data - Why it crashed
- 25. Cache stampeding
- 26. Cache stampeding
- 27. Memcache code ? Memcache code Visitor interface Admin interface DB
- 28. Cache warmup scripts Used to fill your cache when it's empty Run it before starting Webserver ! 2 ways : Visit all URLs Error-prone Hard to maintain Call all cache-updating methods Make sure you have a warmup script !
- 29. Cache stampeding - what about locking ? Seems like a nice idea, but... While lock in place What if the process that created the lock fails ?
- 30. Website X Header Latest news Article content page Navigation Article content
- 31. Website X Header (TTL = 2h) Latest news Article content page Navigation (TTL = 2h) Article content
- 32. Website X Header (TTL = 2h) Latest news (TTL = 2m) Article content page Navigation (TTL = 2h) Article content (TTL = 15m)
- 33. Move the cache
- 34. Varnish Not just a load balancer Reverse proxy cache / http accelerator / … Caches (parts of) pages in memory
- 35. Varnish - ESI In your article page output : Header (TTL : 60 min) <esi:include src="/top"/> /top <esi:include src="/nav"/> Latest news (TTL : 2 min) /news <esi:include src="/news"/> <esi:include src="/article/732"/> Navigation Article content page (TTL : In your Varnish config : 60 min) Article content (TTL : 15 min) sub vcl_fetch { /nav /article/732 if (req.url == "/news") { esi; /* Do ESI processing */ set obj.ttl = 2m; } elseif (req.url == "/nav") { esi; set obj.ttl = 1h; } elseif …. …. }
- 36. A simple benchmark – 2KByte JPEG Apache 2.2 4210 IIS 7.5 3960 Varnish 3.0 11400
- 37. A dynamically generated, but static page Apache 2.2 + PHP (3 DB queries) 18 IIS 7.5 + .Net (3 DB queries) 16 Varnish 3.0 11400
- 38. Varnish - what can/can't be cached ? Can : Static pages Images, js, css Static parts of pages that don't change often (ESI) Can't : POST requests Very large files (it's not a file server !) Requests with Set-Cookie User-specific content
- 39. ESI → no caching on user-specific content ? Logged in as : Wim Godden TTL = 0s ? 5 messages TTL=1h TTL = 5min
- 40. Dynamic content Request Varnish Ideally user X : /top /top request to webserver same user Y : /top /top request to webserver same user X : /top /top request to webserver if unchanged : served from cache user Y : /top /top request to webserver if unchanged : served from cache
- 41. Nginx Web server Reverse proxy Lightweight, fast 12.2% of all Websites
- 42. Nginx No threads, event-driven Uses epoll / kqueue Low memory footprint 10000 active connections = normal
- 43. Coming to Nginx soon... Logged in as : Wim Godden 5 messages Menu NEWS
- 44. Coming to Nginx soon... <esim:include src="/top" session="1" ttl="1h" /> <esim:include src="/menu" <esim:include src="/news" ttl="5m" /> ttl="1h" />
- 45. Requesting /page (1st time) Nginx 1 3 Shared memory /page 2 4 /page
- 46. Requesting /page ESI subrequests (1st time) Nginx 1 2 3 /menu /news /top ($sessionid$)
- 47. Requesting /page (next time) Nginx 1 Shared memory /page 2 /page /menu /news /top ($sessionid$)
- 48. New message arrives... POST /send o ... se i nt t(. e rt ..) ins DB top ($sessionid$)
- 49. Advantages No repeated hits to webserver anymore ! Only the initial hit (unless you pre-heat/warm up the cache !) No hits for user-specific content Not even for non-specific content
- 50. News added addnews() method o ... se i nt t(. e rt ..) ins DB /news
- 51. Advantages No repeated hits to webserver anymore ! Only the initial hit (unless you pre-heat/warm up the cache !) Not for user-specific content Not even for non-specific content No TTLs for non-specific content Imagine doing it for the bid status on Ebay items ;-)
- 52. How many Memcache requests ? Logged in as : Wim Godden <esim:include src="/top" session="1" ttl="1h" /> 5 messages <esim:include src="/menu" <esim:include src="/news" ttl="5m" /> ttl="1h" />
- 53. Why Nginx ? Native Memcache support Excellent and superfast subrequest system Including parallel subrequests Handles thousands of connections per worker With minimal memory footprint
- 54. What's the result ?
- 55. Figures First customer : No. of web servers : 18 → 4 No. of db servers : 6 → 2 Total : 24 → 6 (75% reduction !) Second customer (already using Nginx + Memcache) : No. of web servers : 72 → 8 No. of db servers : 15 → 4 Total : 87 → 12 (86% reduction !)
- 56. Availability Stable at 2 customers Still under heavy development Beta : July 2012 Final : Sep 2012
- 57. So...
- 58. So... There's life outside the MS-box And it's pretty awesome ;-) Need caching in .Net (for DB queries, config-files, etc.) ? Memcache Velocity ? Caching static pages → Varnish with ESI Caching for authenticated users → Nginx with Dynamic ESI There's a lot more outside the box → Maybe some other time ;-)
- 59. Questions ?
- 60. Questions ?
- 61. Contact Twitter @wimgtr Web http://techblog.wimgodden.be Slides http://www.slideshare.net/wimg E-mail [email protected]
- 62. Thanks ! Please rate my talk : http://speakerrate.com/talks/11081