1. PHP, Handle with Care
PBWEB.CO.UK
@PHILL_BROWN

2. What is a PHP Handler?
<?php Interprets Hello
echo ‘Hello’; code

3. It began with CGI

4. CGI
Web server PHP

5. Phoning for a taxi

6. CGI
• Runs PHP on every request
• High CPU
• Doesn’t support PHP accelerators eg APC
• Has security issues

7. An improvement: mod_suphp

8. Apache changes the PHP process owner

9. mod_suPHP
mod_suPHP starts
PHP via CGI
mod_suPHP
Apache PHP changes
process uid

10. Choosing your driver

11. Site 1
cache 757
includes 755
themes 755
Site 2
cache
includes
themes
757
755
755
Without
Apache writable
Site 3
cache 757
includes 755
themes 755

12. Site 1
cache 755
includes 755
Running as file
themes 755
owner
Site 2
cache 755
includes 755
themes 755
Apache writable
Site 3
cache 755
includes 755
themes 755

13. Site 1
cache 775
includes 755
Locking down even
themes 755
Site 2
cache
includes
themes
755
755
755
further
Apache writable
Site 3
cache 755
includes 755
themes 755

14. Create Apache users and site groups
Site1Group
Site1User Site1Apache

15. drwxrwxr-x Site1User Site1Group cache
drwxr-xr-x Site1User Site1Group includes
drwxr-xr-x Site1User Site1Group theme

16. A different approach: mod_php

17. mod_php
Apache Interprets PHP
internally

18. Taking your own car

19. mod_php
• Preloads PHP environment
• Runs as Apache child process = low CPU
• Shared memory
• Supports bytecaching

20. mod_php
• Un-scalable across multiple servers
• Can fill up Apache queue = refused
requests
• Runs as a single user

21. mod_ruid2 - suphp’s better half

22. mod_php + mod_ruid2
Apache mod_php mod_ruid2
Change process uid

23. Your own chauffeur

24. FastCGI - nu school

25. FastCGI
Runs PHP in a
Web server FCGI server persistent FastCGI
process

26. Being at a taxi rank
LOADS
OF TAXIS

27. FastCGI
• Separates PHP from static requests
• Uses persistent processes
• Highly configurable
• Lower CPU but higher memory usage

28. Benefit of separation
Client
Request
static HTML PHP
Internal HTTP
FCGI server
server

29. FastCGI Process Manager:
adaptable process spawning

30. Summary
CGI suPHP DSO ruid2 fCGI FPM
CPU usage
Supports PHP Accelerators
Run as file owner
Separation of interpreter and
server
Server agnostic
Memory usage

31. Handling questions..
Intensive processing
Probable
Question? Phill
memory leak
ask
PBWEB.CO.UK
@PHILL_BROWN