1. Shoehorning Apache Onto Your Box System Sizing Tips Sander Temme

2. So, your web server machine may not be the fastest, shiniest machine, but it can still take a few hits without going down.

3. 3 Assumptions Limited Resources Work With What You Have You’re probably running Linux No Compiling or Recompiling! You can find httpd.conf

4. 4 Purposes of Monitoring Observation Extrapolation Signals/Alerts Testing

5. 5 Monitoring Your Server

6. 6 Monitoring Apache

7. 7 Monitoring: Nagios

8. 8 Other Monitoring Tools vmstat top free

9. 9 Web Server Logs ErrorLog –LogLevel: debug, info, notice, warn, error, crit Access Log: TransferLog or CustomLog –Common Log Format

10. 10 Common Log Format 172.16.2.91 - - [16/Nov/2003:15:23:27 -0800] "GET /~sctemme/ HTTP/1.1" 200 1446 172.16.2.91 - - [16/Nov/2003:15:23:28 -0800] "GET /~sctemme/css/doc.css HTTP/1.1" 200 167 172.16.2.91 - - [16/Nov/2003:15:23:28 -0800] "GET /~sctemme/css/menu.css HTTP/1.1" 200 623 172.16.2.91 - - [16/Nov/2003:15:23:29 -0800] "GET /favicon.ico HTTP/1.1" 404 283 172.16.2.91 - - [16/Nov/2003:15:23:34 -0800] "GET /~sctemme/index.html HTTP/1.1" 200 1446 Client IP172.16.2.91 RFC 1413 ident- username- timestamp[16/Nov/2003:15:23:29 -0800] Request"GET /favicon.ico HTTP/1.1" Status Code404 Content Bytes283

11. 11 Configuring for Performance Configuring Apache Tuning the Operating System Scaling Your Site

12. 12 Apache Configuration Process/Thread Management DNS Lookups Avoid.htaccess Files Disable unused modules Tune your App Tier Cache if you Can

13. 13 DNS Lookups HostnameLookups Access Control –Bad: Deny from example.com –Good: Deny from 172.160.234.5

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

15. 15 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)

16. 16 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

17. 17 Top

18. 18 Tune your App Tier Tomcat –Edit server.xml, tune minProcessors, maxProcessors –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

19. 19 Cache your Content Dynamic Content is Expensive Static Content is Cheap Don’t Regenerate the Same Page –Cache it! –Wiki, Blog, Catalogs, … Example: wiki.apache.org

20. 20 System Tuning Tips RAM and swap space ulimit: files and processes Turn off unused services and modules Patch your OS

21. 21 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

22. 22 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 2.0 startup script –ulimit -S -n `ulimit -H -n` Linux: /etc/security/limits.conf

23. 23 Example: ajax.apache.org 4xItanium CPU HP Integrity Server, 8Gb RAM RHEL 3.0 www.apache.org, most TLPs, JIRA, Bugzilla, Wiki Very beefy machine Does not perform well –Especially disk access Upgrade to RHEL 4.0? (future) JIRA Upgrade Helped Cache for Wiki Helped Wiki under mod_pyton? (future?) …

24. 24 Scaling Your Site Vertically –Tiered Model Horizontally –Load Balancing

25. 25 Scaling Vertically Client TCP/IP

26. 26 Scaling Vertically Move Services to Other Hosts Pros: –Less resource contention –Specialized hardware –Scale tiers individually Cons: –Development/Deployment harder –More hosts to manage

27. 27 Scaling Horizontally Client

28. 28 Tips Observe Before You Act Act on Monitoring Results Don’t Overload Your System Use A Staging Server

29. Q&A

30. 30 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

31. 31 Conference Roadmap T20:Scalable Internet Architectures WE04:QoS management of Internet services WE09:Troubleshooting Apache configurations TH01:Scaling Apache 2.x to > 20,000 concurrent downloads TH17:Caching, Tips for Improving Performance TH21:Powering High-volume web sites with Lenya/Cocoon and mod_cache FR05:Improving Web Performance with Dynamic Compression FR09:Clustering and load balancing using mod_proxy

32. Current Version http://apache.org/~sctemme/ApconEU2005/WE05/

33. Thank You

34. Backup Slides

35. 35 Selecting Your MPM Apache 2.0 only! Processes and Threads Differences between platforms Thread-safety issues

36. 36 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

37. 37 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

38. 38 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 –Use KSE threading in 5.x –Still not endorsed by ASF