rasmus Wed Dec 22 10:03:21 2004 EDT
Modified files:
/phpdoc/en language-snippets.ent
/phpdoc/en/faq installation.xml
Log:
Restrict the Apache2 warning to just talk about threading issues.
http://cvs.php.net/diff.php/phpdoc/en/language-snippets.ent?r1=1.125&r2=1.126&ty=u
Index: phpdoc/en/language-snippets.ent
diff -u phpdoc/en/language-snippets.ent:1.125
phpdoc/en/language-snippets.ent:1.126
--- phpdoc/en/language-snippets.ent:1.125 Mon Dec 13 10:06:21 2004
+++ phpdoc/en/language-snippets.ent Wed Dec 22 10:03:20 2004
@@ -1,4 +1,4 @@
-<!-- $Revision: 1.125 $ -->
+<!-- $Revision: 1.126 $ -->
<!-- Keep 'em sorted -->
@@ -413,9 +413,9 @@
utf16le, utf16be, big5 and shiftjis.</para>'>
<!-- Snippets for the installation section -->
-<!ENTITY warn.apache2.compat '<warning><para>Do not use Apache 2.0.x
-and PHP in a production environment neither on Unix nor on Windows. For
-information on why, read the following
+<!ENTITY warn.apache2.compat '<warning><para>We do not recommend using a
threaded MPM
+in production with Apache2. Use the prefork MPM instead, or use Apache1. For
information
+on why, read the following
<link linkend="faq.installation.apache2">FAQ entry</link></para></warning>'>
<!ENTITY note.apache.slashes '<note><simpara>Remember that when adding
http://cvs.php.net/diff.php/phpdoc/en/faq/installation.xml?r1=1.40&r2=1.41&ty=u
Index: phpdoc/en/faq/installation.xml
diff -u phpdoc/en/faq/installation.xml:1.40 phpdoc/en/faq/installation.xml:1.41
--- phpdoc/en/faq/installation.xml:1.40 Sun Sep 19 06:08:19 2004
+++ phpdoc/en/faq/installation.xml Wed Dec 22 10:03:21 2004
@@ -1,5 +1,5 @@
<?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.40 $ -->
+<!-- $Revision: 1.41 $ -->
<chapter id="faq.installation">
<title>Installation</title>
<titleabbrev>Installation</titleabbrev>
@@ -22,60 +22,11 @@
<qandaentry id="faq.installation.apache2">
<question>
<para>
- Why shouldn't I use Apache 2 in a production environment?
+ Why shouldn't I use Apache2 with a threaded MPM in a production
environment?
</para>
</question>
<answer>
<para>
- The following answer is based in this modified excerpt of a mail
- by Rasmus Lerdorf.
- </para>
- <para>
- Apache 2 is a complete rewrite and a complete architecture change from
- Apache 1. It is not like going from PHP 3 to PHP 4 or from PHP 4 to PHP
5.
- There is a lot of code that is common, and certainly the base
architecture
- of PHP has not changed for years. So comparing Apache 1 vs. Apache 2 to
- PHP 4 vs. PHP 5 makes no sense. The architecture has been proven over
- the years and the code, while somewhat unwieldy in places, is a known
- entity. PHP from the very early days was designed against this basic
- Apache 1 architecture and works extremely well running under it.
- </para>
- <para>
- The major feature that draws people to Apache 2 is threading. On Windows
- where most basic libraries are, and must be, threadsafe, Apache 2 does
- actually make sense and it would be good to work out the kinks on that
- platform. However, on UNIX there are a lot of basic libraries where
- thread safety is an unknown. And this is not about PHP extensions, it is
- about 3rd-party libraries underneath PHP's hundreds of extensions.
- Whether any one 3rd-party library is threadsafe is really hard to
- determine. There are a lot of variables involved, including which OS,
- which version of the OS, which libc, which version of that libc and on
- some platforms even the compiler flags used to compile these things. And
- to make it even more fun, tracking down a thread safety problem is damn
- well near impossible. Hundreds of people may well state that
- Apache+PHP+ext/foo works perfectly for them, but maybe they are only
- getting about a million hits a day. Then another user comes along who
- gets 100 million hits a day and uses a fast dual-cpu machine and
- everything blows up because now suddenly the window for some tiny race
- condition has been made much larger due to the faster cpu speeds, the
- second cpu and the higher frequency of requests. And the bug report we
- get from this user will be something along the lines of:
- </para>
- <blockquote>
- <para>
- It don't work sometimes. Most of the times it works fine, but then
- every now and then it just don't. The error is different each time
- and I have no idea how to reproduce it, but fix it right away!!!
- </para>
- </blockquote>
-
- <para>What can we do about these?</para>
- <para>
- There are a number of (fixable) technical reasons Rasmus does not think
- Apache2+PHP is a good idea in a production environment, but setting
- those aside it really boils down to one simple concept:
- </para>
- <para>
PHP is glue. It is the glue used to build cool web applications by
sticking dozens of 3rd-party libraries together and making it all appear
as one coherent entity through an intuitive and easy to learn language
@@ -83,18 +34,18 @@
robustness of the underlying platform. It needs a working OS, a working
web server and working 3rd-party libraries to glue together. When any of
these stop working PHP needs ways to identify the problems and fix them
- quickly. By making the underlying framework more complex by not having
+ quickly. When you make the underlying framework more complex by not
having
completely separate execution threads, completely separate memory
- segments and a strong sandbox for each request to play in, a feet of
- clay is introduced into PHP's system.
+ segments and a strong sandbox for each request to play in, feet of
+ clay are introduced into PHP's system.
+ </para>
+ <para>
+ If you feel you have to use a threaded MPM, look at a FastCGI
configuration
+ where PHP is running in its own memory space.
</para>
<para>
- Using the prefork mpm with Apache 2 to avoid the threading is possible,
- and yes using a standalone fastcgi mechanism to avoid the threading,
- too, but then defining characteristic of the web server of choice are
- avoided. At this point in its development, Rasmus still maintains that
- one is better off simply sticking with Apache 1 for serving up PHP pages
- with the one caveat that Apache 1 sucks pretty badly on Windows.
+ And finally, this warning against using a threaded MPM is not as strong
for
+ Windows systems because most libraries on that platform tend to be
threadsafe.
</para>
</answer>
</qandaentry>
