From: Ken Coar Date: Tue, 8 Apr 1997 04:48:15 +0000 (+0000) Subject: Latest version of the Apache FAQ. Not the ultimate, but enough for X-Git-Tag: APACHE_1_2b9~76 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=50221b779dcfa3aa871e0c87f45cfcc1ef6c12aa;p=apache Latest version of the Apache FAQ. Not the ultimate, but enough for now, and somewhat improved over what's there. More to come soon. Reviewed by: Roy Fielding, Paul Sutton git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@77815 13f79535-47bb-0310-9956-ffa450edef68 --- diff --git a/docs/manual/misc/FAQ.html b/docs/manual/misc/FAQ.html index bd0ea25e66..0c553f7c6c 100644 --- a/docs/manual/misc/FAQ.html +++ b/docs/manual/misc/FAQ.html @@ -1,158 +1,504 @@ - + -Apache server Frequently Asked Questions +Apache Server Frequently Asked Questions -

Apache server Frequently Asked Questions

Apache Server Frequently Asked Questions

The Questions

What is Apache ? -
Why was Apache created ? -
How does the Apache group relate to other servers ? -
Why the name "Apache" ? -
How compatible is Apache with my existing NCSA 1.3 setup ? -
OK, so how does Apache compare to other servers ? -
How thoroughly tested is Apache? -
Does or will Apache act as a Proxy server? -
What are the future plans for Apache ? -
Who do I contact for support ? -
Is there any more information on Apache ? -
Where can I get Apache ? -

- -

The Answers

What is Apache ? -
- Apache was originally based on code and ideas found in the most -popular HTTP server of the time.. NCSA httpd 1.3 (early 1995). It has -since evolved into a far superior system which can rival (and probably -surpass) almost any other UNIX based HTTP server in terms of functionality, -efficiency and speed. -
Since it began, it has been completely rewritten, and includes many new -features. Apache is, as of November 1996, the most popular WWW server on -the Internet, according to the Netcraft Survey. - -
-
-
How does the Apache group relate to other -server efforts, such as NCSA's? -
-We, of course, owe a great debt to NCSA and their programmers for -making the server Apache was based on. We now, however, have our own -server, and our project is mostly our own. The Apache Project is an -entirely independent venture. -
-
- -
Why was Apache created ? -
to address concerns of a group of www providers and part time httpd -programmers, that httpd didn't behave as they wanted it -to. Apache is an entirely volunteer effort, completely funded by its -members, not by commercial sales. -
- -
- -
Why the name "Apache" ? -
A cute name which stuck. Apache is "A PAtCHy server". It was - based on some existing code and a series of "patch files". -
-
- - -
How compatible is Apache with my existing NCSA 1.3 -setup ?
- -Apache attempts to offer all the features and configuration options -of NCSA httpd 1.3, as well as many of the additional features found in -NCSA httpd 1.4 and NCSA httpd 1.5.
- -NCSA httpd appears to be moving toward adding experimental features -which are not generally required at the moment. Some of the experiments -will succeed while others will inevitably be dropped. The Apache philosophy is -to add what's needed as and when it is needed.
- -Friendly interaction between Apache and NCSA developers should ensure -that fundamental feature enhancments stay consistent between the two -servers for the foreseeable future.
- -
- -
OK, so how does Apache compare to other servers ? -
-For an independent assessment, see http://webcompare.iworld.com/compare/chart.html -
- -
Apache has been shown to be substantially faster than many other -free servers. Although certain commercial servers have claimed to -surpass Apache's speed (it has not been demonstrated that any of these -"benchmarks" are a good way of measuring WWW server speed at any -rate), we feel that it is better to have a mostly-fast free server -than an extremely-fast server that costs thousands of dollars. Apache -is run on sites that get millions of hits per day, and they have -experienced no performance difficulties.
- -
-
How thoroughly tested is Apache? - -
Apache is run on over 200,000 Internet servers (as of November 1996). It has -been tested thoroughly by both developers and users. The Apache Group -maintains rigorous standards before releasing new versions of their -server, and our server runs without a hitch on over one third of all -WWW servers. When bugs do show up, we release patches and new -versions, as soon as they are available. - -
See http://www.apache.org/info/apache_users.html for an incomplete list of sites running Apache.
- -
- -
Does or will Apache act as a Proxy server? -
Apache version 1.1 -and above comes with a proxy module. If compiled in, this will make -Apache act as a caching-proxy server -
-
- -
What are the future plans for Apache ? -
- to continue as a public domain HTTP server, -
- to keep up with advances in HTTP protocol and web developments in general -
- to collect suggestions for fixes/improvements from its users, -
- to respond to needs of large volume providers as well as occasional users. + + + + + + + + + + + + + +
  - Background +
    +
  - Technical Questions +
    +
  -
  -
- Who do I contact for support ? -
  There is no official support for Apache. None of the developers want to -be swamped by a flood of trivial questions that can be resolved elsewhere. -Bug reports and suggestions should be sent via the bug report page. -Other questions should be directed to -comp.infosystems.www.servers.unix, where some of the Apache team lurk, -in the company of many other httpd gurus who should be able -to help. -
  -Commercial support for Apache is, however, available from a number -third parties. -
  
  -
- Is there any more information on Apache ? -
  Indeed there is. See http://www.apache.org/. -
  -
  - -
- Where can I get Apache ? +
  The Answers
  
  -You can find the source for Apache at http://www.apache.org/.
  +
  + Background +
  +
  1. What is Apache? +
    + Apache was originally based on code and ideas found in the most + popular HTTP server of the time.. NCSA httpd 1.3 (early 1995). It has + since evolved into a far superior system which can rival (and probably + surpass) almost any other UNIX based HTTP server in terms of functionality, + efficiency and speed. +
    +
    + Since it began, it has been completely rewritten, and includes many new + features. Apache is, as of January 1997, the most popular WWW server on + the Internet, according to the + Netcraft Survey. +
    +
    +
  2. Why was Apache created? +
    + To address the concerns of a group of WWW providers and part-time httpd + programmers that httpd didn't behave as they wanted it to behave. + Apache is an entirely volunteer effort, completely funded by its + members, not by commercial sales. +
    +
    +
  3. How does The Apache Group's work relate to other + server efforts, such as NCSA's? +
    + We, of course, owe a great debt to NCSA and their programmers for + making the server Apache was based on. We now, however, have our own + server, and our project is mostly our own. The Apache Project is an + entirely independent venture. +
    +
    +
  4. Why the name "Apache"? +
    + A cute name which stuck. Apache is "A + PAtCHy server". It was + based on some existing code and a series of "patch files". +
    +
    +
  5. OK, so how does Apache compare to other servers? +
    + For an independent assessment, see + http://webcompare.iworld.com/compare/chart.html. +
    +
    + Apache has been shown to be substantially faster than many other + free servers. Although certain commercial servers have claimed to + surpass Apache's speed (it has not been demonstrated that any of these + "benchmarks" are a good way of measuring WWW server speed at any + rate), we feel that it is better to have a mostly-fast free server + than an extremely-fast server that costs thousands of dollars. Apache + is run on sites that get millions of hits per day, and they have + experienced no performance difficulties. +
    +
    +
  6. How thoroughly tested is Apache? +
    + Apache is run on over 400,000 Internet servers (as of April 1997). It has + been tested thoroughly by both developers and users. The Apache Group + maintains rigorous standards before releasing new versions of their + server, and our server runs without a hitch on over one third of all + WWW servers available on the Internet. When bugs do show up, we + release patches and new versions as soon as they are available. +
    +
    + See + http://www.apache.org/info/apache_users.html + for a partial list of sites running Apache. +
    +
    +
  7. What are the future plans for Apache? +
    +
    - to continue as a public domain HTTP server, +
    - to keep up with advances in HTTP protocol and web developments in + general +
    - to collect suggestions for fixes/improvements from its users, +
    - to respond to needs of large volume providers as well as + occasional users. +
    +
    +
    +
  8. Whom do I contact for support? +
    + There is no official support for Apache. None of the developers want to + be swamped by a flood of trivial questions that can be resolved elsewhere. + Bug reports and suggestions should be sent via + the bug report page . + Other questions should be directed to the + comp.infosystems.www.servers.unix + newsgroup, where some of the Apache team lurk, + in the company of many other httpd gurus who should be able + to help. +
    +
    + Commercial support for Apache is, however, available from a number + of third parties. +
    +
    +
  9. Is there any more information available on Apache? +
    + Indeed there is. See the main Apache Web site at + http://www.apache.org/. + There is also a regular electronic publication called Apache + Week available; you can find out more about this at + http://www.apacheweek.com/. +
    +
    +
  10. Where can I get Apache? +
    + You can find the source for Apache at the main web page, + http://www.apache.org/. +
    +
    +
  +
  + Technical Questions +
  +
  1. "Why can't I ...? Why won't ... work?" What to + do in case of problems +
    + If you are having trouble with your Apache server software, you should + take the following steps: +
    +
    1. Check the errorlog! +
      + Apache tries to be helpful when it encounters a problem. In many + cases, it will provide some details by writing one or messages to + the server error log (see the + ErrorLog + directive). Somethimes this is enough for you to diagnose & + fix the problem yourself (such as file permissions or the like). +
      +
    2. Check the Apache bug database +
      + Most problems that get reported to The Apache Group are recorded in + the bug database (available at + http://www.apache.org/bugdb.cgi). + Please check the existing reports, open + and closed, before adding one. If you find + that your issue has already been reported, please don't add + a "me, too" report. If the original report isn't closed + yet, we suggest that you check it periodically. You might also + consider contacting the original submittor, because there may be an + email exchange going on about the issue that isn't getting recorded + in the database. +
      +
    3. Ask in the comp.infosystems.www.servers.unix + USENET newsgroup +
      + A lot of common problems never make it to the bug database because + there's already high Q&A traffic about them in the + comp.infosystems.www.servers.unix + newsgroup. Many Apache users, and some of the developers, can be + found roaming its virtual halls, so it is suggested that you seek + wisdom there. The chances are good that you'll get a faster answer + there than from the bug database, even if you don't see + your question already posted. +
      +
    4. If all else fails, report the problem in the bug + database +
      + If you've gone through those steps above that are appropriate and + have obtained no relief, then please do let The Apache + Group know about the problem by logging a bug report (see + http://www.apache.org/bugdb.cgi). +
      +
      + If your problem involves the server crashing and generating a core + dump, please include a backtrace (if possible). As an example, +
      +
```
+     # cd ServerRoot
+     # dbx httpd core
+     (dbx) where
+    
```
      +
      + (Substitute the appropiate locations for your + ServerRoot and your httpd and + core files.) +
      +
    +
    +
  2. How compatible is Apache with my existing NCSA 1.3 + setup? +
    + Apache attempts to offer all the features and configuration options + of NCSA httpd 1.3, as well as many of the additional features found in + NCSA httpd 1.4 and NCSA httpd 1.5. +
    +
    + NCSA httpd appears to be moving toward adding experimental features + which are not generally required at the moment. Some of the experiments + will succeed while others will inevitably be dropped. The Apache + philosophy is to add what's needed as and when it is needed. +
    +
    + Friendly interaction between Apache and NCSA developers should ensure + that fundamental feature enhancments stay consistent between the two + servers for the foreseeable future. +
    +
    +
  3. What does it mean when my CGIs fail with "Premature + end of script headers"? +
    +
    +
    + It means just what it says: the server was expecting a complete set of + HTTP headers (one or more followed by a blank line), and didn't get + them. The most common cause of this is Perl scripts which haven't + disabled buffering; if you insert the following statements before your + first print statement, this will probably go away. +
    +
```
+   $cfh = select (STDOUT);
+   $| = 1;
+   select ($cfh);
+  
```
    +
    + If your script isn't written in Perl, do the equivalent thing for + whatever language you are using (e.g., for C, call + fflush() after writing the headers). +
    +
    +
  4. How do I enable SSI (parsed HTML)? +
    +
    +
    +
  5. Why don't my parsed files get cached? +
    + Since the server is performing run-time processing of your SSI + directives, which may change the content shipped to the client, it + can't know at the time it starts parsing what the final size of the + result will be, or whether the parsed result will always be the same. + This means that it can't generate Content-Length or + Last-Modified headers. Caches commonly work by comparing + the Last-Modified of what's in the cache with that being + delivered by the server. Since the server isn't sending that header + for a parsed document, whatever's doing the caching can't tell whether + the document has changed or not - and so fetches it again to be on the + safe side. +
    +
    + You can work around this in some cases by causing an + Expires header to be generated. (See the + mod_expires + documentation for more details.) +
    +
    +
  6. How can I have my script output parsed? +
    + So you want to include SSI directives in the output from your CGI + script, but can't figure out how to do it? + The short answer is "you can't." This has been regarded as a + security liability, and the basic solution is for your script itself to do + what the SSIs would be doing. After all, it's generating the + rest of the content. +
    +
    +
  7. Does or will Apache act as a Proxy server? +
    + Apache version 1.1 and above comes with a proxy module. If compiled + in, this will make Apache act as a caching-proxy server. This module + is still considered experimental, however. +
    +
    +
  8. What are "multiviews"? +
    + "Multiviews" is the general name given to the Apache + server's ability to provide language-specific document variants in + response to a request. This is documented quite thoroughly in the + content negotiation + description page. +
    +
    +
  9. Why can't I run more than <n> + virtual hosts? +
    + The Apache server can behave unpredictably when it encounters some + resource limitations. One of these is the per-process limit + on file descriptors, and that's almost always the + cause of problems seen when adding virtual hosts. In this + case, it is not actually Apache that's encountering the problem, but + typically some library routine (such as gethostbyname()) + which needs file descriptors and doesn't complain intelligibly when it + can't get them. +
    +
    + Each virtual host requires several file descriptors for housekeeping + functions, in addition to those actually used to serve files to + clients. +
    +
    + Typical values for <n> that we've seen are in + the neighbourhoods of 128 or 250. When the server bumps into the file + descriptor limit, it may dump core with a SIGSEGV, or it might just + hang, or it may limp along and you'll see (possibly meaningful) errors + in the error log. +
    +
    + As to what you can do about this: +
    +
    1. Increase the number of file descriptors available to the server + (see your system's documentation on the limit or + ulimit commands) +
    2. "Don't do that" - try to run with fewer virtual hosts +
    3. Spread your operation across multiple server processes and/or ports +
    +
    + Since this is an operating-system limitation, there's not much else + available in the way of solutions. +
    +

Apache server Frequently Asked Questions

Apache Server Frequently Asked Questions

The Questions

The Answers

The Answers

+ Background +

+ Technical Questions +