The document discusses scalability and reverse proxies. It provides information on Pressflow, Varnish, and Nginx as reverse proxy options. It includes configuration examples and optimizations for using Varnish as a reverse proxy with Pressflow to improve scalability and performance.

1. Scalability is the new black

2. Scalability is a desirable property of a system, a network, or a process, which indicates its ability to either handle growing amounts of work in a graceful manner or to be enlarged. What is scalability? -Wikipedia

5. Better session handling

8. Delay between corresponding prefflow forks and vanilla Drupal

9. Patch compatibility is not 100% guaranteed

11. if you need the features of PF

13. if you need the features of PF

14. No

15. if you are afraid of experimental and 3 rd party code for the site

18. Squid – most used proxy

19. Varnish – mostly used with Drupal sites

20. Nginx – http and proxy server in one

22. Almost out of the box compatibility with Pressflow (and Drupal 7)

23. Surpassed only by nginx with a very small margin

24. Very helpful tools (varnishtop, varnishhist etc)

26. Configuration looks difficult at first

27. A little slower than nginx

28. Needs a backend

30. # apt-get -t testing install varnish

31. Configure diffrent listening port for apache if they share the same environment

32. Configure Varnish to forward traffic to the Apache's server IP and Port

34. Set the Caching Mode to External

35. Set the Page Cache Maximum Age > 0

37. Static files should have expire headers for correct varnish cache life

38. Avoid non 2xx request status, like 3xx redirects.

39. Choose carefully the Minimum cache lifetime in Pressflow

40. backend default { .host = &quot;<ApacheIP&quot;; .port = &quot;80&quot;; .connect_timeout = 120s; .first_byte_timeout = 60s; .between_bytes_timeout = 20s; .max_connections = 95; } sub vcl_hash { if (req.http.Cookie) { set req.hash += req.http.Cookie; } } sub vcl_fetch { if (req.url ~ &quot;(png|gif|jpg|swf|css|js)$&quot;) { unset beresp.http.set-cookie; } }

41. sub vcl_recv { if (req.request != &quot;GET&quot; && req.request != &quot;HEAD&quot; && req.request != &quot;PUT&quot; && req.request != &quot;POST&quot; && req.request != &quot;TRACE&quot; && req.request != &quot;OPTIONS&quot; && req.request != &quot;DELETE&quot;) { /* Non-RFC2616 or CONNECT which is weird. */ return (pipe); } if (req.request != &quot;GET&quot; && req.request != &quot;HEAD&quot;) { /* We only deal with GET and HEAD by default */ return (pass); } if (req.url ~ &quot;(png|gif|jpg|swf|css|js)$&quot;) { unset req.http.Cookie; return (lookup); } set req.http.Cookie = regsuball(req.http.Cookie, &quot;(^|;*)(__[a-z]+)=[^;]*&quot;, &quot;&quot;); set req.http.Cookie = regsuball(req.http.Cookie, &quot;(^|;*)(slider-block_1)=[^;]*&quot;, &quot;&quot;); set req.http.Cookie = regsuball(req.http.Cookie, &quot;(^|;*)(DrupalAdminToolbar)=[^;]*&quot;, &quot;&quot;); set req.http.Cookie = regsub(req.http.Cookie, &quot;^;*&quot;, &quot;&quot;); if (req.http.Cookie ~ &quot;^*$&quot;) { unset req.http.Cookie; }

42. if (req.http.Authorization || req.http.Cookie) { return (pass); } if (req.url ~ &quot;installphp|updatephp|cronphp&quot;) { return (pass); } if (req.http.Accept-Encoding) { if (req.url ~ &quot;(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$&quot;) { # No point in compressing these remove req.http.Accept-Encoding; } elsif (req.http.Accept-Encoding ~ &quot;gzip&quot;) { set req.http.Accept-Encoding = &quot;gzip&quot;; } else { remove req.http.Accept-Encoding; } } set req.grace = 30s; return (lookup); }

43. Varnish tools - varnishhist

44. Varnish - varnishtop

45. Varnish – varnishtop -i TxURL

46. Varnish - varnishstat

48. Nginx with boost : 1678.02 Request / Second

49. Rackspace Instance 2048MB (88$/month)

50. Apache with Boost : 54.77 Request / Second

51. Questions? Stefanos Boglou