The document discusses various techniques for optimizing Apache web server performance, including: 1) Monitoring tools like vmstat and top to observe server performance and detect issues. 2) Analyzing web server logs using tools like Webalizer to understand traffic patterns. 3) Configuring Apache settings like threads and processes based on the platform. 4) Caching static content and pre-rendering dynamic pages to reduce load on the server.

1. Apache Performance Tuning Part 1: Scaling Up Sander Temme <sander@temme.net>

2. Who am I? Member, Apache Software Foundation Lurker on dev@httpd Infrastructure Team Member Contractor Walt Disney Imagineering ADP University of California Currently unemployed…

3. “ Apache is a general webserver, which is designed to be correct first, and fast second. Even so, its performance is quite satisfactory. Most sites have less than 10Mbits of outgoing bandwidth, which Apache can fill using only a low end Pentium-based webserver.” http://httpd.apache.org/docs/1.3/misc/perf-tuning.html says:

5. Goals of Performance Tuning Serve as Many Requests as Possible Graceful Degradation (Don’t crash the box)

6. Assumptions Limited Resources Work With What You Have You’re probably running Linux No Compiling or Recompiling! You can find httpd.conf

7. Monitoring Your Server

8. Purposes of Monitoring Observation Extrapolation Signals/Alerts Testing

9. Monitoring Apache

10. Monitoring Solaris: SE Toolkit Lightweight Programmable Alive http://www.sunfreeware.com/setoolkit.html

11. Other Monitoring Tools vmstat iostat top free

12. Web Server Logs ErrorLog LogLevel: debug, info, notice, warn, error, crit Access Log : TransferLog or CustomLog Common Log Format

13. Common Log Format 172.16.2.91 - - [16/Nov/2003:15:23:27 -0800] &quot;GET /~sctemme/ HTTP/1.1&quot; 200 1446 172.16.2.91 - - [16/Nov/2003:15:23:28 -0800] &quot;GET /~sctemme/css/doc.css HTTP/1.1&quot; 200 167 172.16.2.91 - - [16/Nov/2003:15:23:28 -0800] &quot;GET /~sctemme/css/menu.css HTTP/1.1&quot; 200 623 172.16.2.91 - - [16/Nov/2003:15:23:29 -0800] &quot;GET /favicon.ico HTTP/1.1&quot; 404 283 172.16.2.91 - - [16/Nov/2003:15:23:34 -0800] &quot;GET /~sctemme/index.html HTTP/1.1&quot; 200 1446 283 Content Bytes 404 Status Code &quot;GET /favicon.ico HTTP/1.1&quot; Request [16/Nov/2003:15:23:29 -0800] timestamp - username - RFC 1413 ident 172.16.2.91 Client IP

14. Log File Analysis Analog Fast Cryptic output Webalizer Not as fast Nicer output Patched version available w/ GeoIP, DNS, 404 support (Google for it) http://www.mrunix.net/webalizer/ http://www.analog.cx/

15. Webalizer Output

16. Webalizer Output Detail

17. Configuring for Performance Configuring Apache Tuning the Operating System

18. Apache Configuration Process/Thread Management DNS Lookups Avoid .htaccess Files Disable unused modules Tune your App Tier

19. Selecting Your MPM Apache 2.x only! Processes and Threads Differences between platforms Thread-safety issues

20. Processes and Threads Process: Own copy of data structures Shares: program code, shared memory Context switches expensive Thread: Runs within process Shares process environment No context switch

21. Platforms and Threading Context switches expensive on Solaris, AIX Context switches cheaper on Linux Solaris uses M:N threading Linux uses 1 process per thread LinuxThreads implementation is old Replaced by Native Posix Thread Library (NPTL) in 2.6 NTPL already in RH 9, RHAS 3

22. Thread-safety Third-party modules and libraries mod_perl: experimental threading in Perl 5.6; more mature in Perl 5.8 PHP: uses many third-party libraries FreeBSD: threading not reliable until 5.x Apache 2.2 Worker MPM runs on FreeBSD

23. MaxClients Configuration file directive Maximum number of workers Apache 1.3, 2.0 Prefork: processes Apache 2.0 Worker: threads * processes Limit according to resources (memory)

24. Sizing MaxClients Take total RAM Subtract OS allowance look at free value without Apache, etc. Subtract external program allowance JVM, cgi programs, MySQL? Divide by httpd process size Read process size from top

25. Top

26. DNS Lookups HostnameLookups Access Control Bad: Deny from example.com Good: Deny from 172.160.234.5

27. .htaccess Files Per-directory configuration files Accessed for every request Best performance: AllowOverride none GET /dir1/dir2/restricted.html HTTP/1.0

28. Server-side Includes We Love Them! Easy to implement Easy to manage We Hate Them! They break sendfile() They break cacheability Use XBitHack Directive Only parse executable text/html type files Special treatment of Last-modified date

29. SSI on www.apache.org SSI Enabled

30. Tune your App Tier Tomcat Edit server.xml, tune minProcessors, maxProcessors Use APR -> Persistent connections Tune JVM (Heap, Garbage Collection) MySQL Ships with various scenarios in support-files: my-{small,medium,large,huge}.conf PHP & prefork: every child makes a connection Tune max_connections variable in my.cnf

31. System Tuning Tips RAM and swap space ulimit: files and processes Turn off unused services and modules

32. RAM and Swap Swap is disk-based Extension of RAM Excessive swapping kills performance Tune MaxClients Never have more memory than swap Upgrade RAM -> add more swap space

33. ulimit Per-process resource limits Built-in command of sh, bash Important limits: processes (-u) open files (-n) Set in invoking shell Code in Apache 2 startup script ulimit -S -n `ulimit -H -n` Linux: /etc/security/limits.conf

34. Caching Content Dynamic Content is Expensive Static Content Relatively Cheap Several Approaches: Dynamic caching Pre-rendering popular pages (index.rss…)

35. mod_cache Configuration <IfModule mod_cache.c> <IfModule mod_disk_cache.c> CacheRoot /raid1/cacheroot CacheEnable disk / # A page modified 100 min. ago will expire in 10 min. CacheLastModifiedFactor .1 # Always check again after 6 hours CacheMaxExpire 21600 </IfModule> </IfModule>

36. Make Popular Pages Static RSS Feeds Popular catalog queries … (Check your access log)

37. Static Page Substitution <Directory &quot;/home/sctemme/inst/blog/httpd/htdocs&quot;> Options +Indexes Order allow,deny Allow from all RewriteEngine on RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)$ /cgi-bin/blosxom.cgi/$1 [L,QSA] </Directory>

38. Tips Observe Before You Act Act on Monitoring Results Don’t Overload Your System

39. Q&A

40. Conference Roadmap TU1 30 Top PHP Scalability Mistakes WE3 CNN.com Performance and Lessons Learned WE8 Hacking the Apache HTTP Server at Yahoo! WE24 Essentials on Performant JavaServer™ Faces Apps: Client Versus Server Side TH1 Httpd Power Tools TH4 mod_perl for Speed Freaks! TH7 2.2 Rocks! Quit using 1.3 already! TH9 mod_perl-2.0: Advanced Profiling & Instrumenting Techniques

41. Current Version http://people.apache.org/~sctemme/ApconUS2006/WE18/

42. Thank You

43. Further Reading Ryan B. Bloom, Apache Server 2.0: The Complete Reference , 2002 McGraw Hill Osborne; ISBN 0-07-222344-8 Ben Laurie and Peter Laurie, Apache: The Definitive Guide (3rd Edition) , 2002 O’Reilly & Associates; ISBN 0596002033 Patrick Killelea, Web Performance Tuning, 2nd Edition , 2002 O’Reilly & Associates; ISBN 0-596-00172-X http://httpd.apache.org/docs-2.0/misc/perf-tuning.html http://httpd.apache.org/docs/misc/perf-tuning.html Adrian Cockcroft, Richard Pettit and Sun Microsystems Press, Sun Performance and Tuning: Java and the Internet (2nd Edition) , 1998 Prentice Hall PTR; ISBN 0130952494 Ken Coar and Rich Bowen, Apache Cookbook , 2003 O’Reilly & Associates; ISBN 0596001916