Large Resource Consumption by One User Access to mp3 File

[Greg Sims <gr...@headingup.net>]

I originally posted this to the User Support forum and received no replies
in over two weeks.  I appreciate your help with this in advance!
 
The Apache Service is stopping as a result of a single user accessing one or
two mp3 files.  I gathered some log data to detail the problem:
 
http://raystedman.org/4204Ref.txt  contains a log sequence that accesses one
mp3 file by one user.
 
http://raystedman.org/mp3/4204.mp3 is the mp3
<http://raystedman.org/mp3/4204.mp3%20is%20the%20mp3>  being accesses which
is almost 7 MB large.  
 
Normally I will only see one record in the access_log for a transfer like
this one.  This transfer contains 30+ records over 12 minutes from the same
user to the same file.  It may be that this user is one a system with
limited buffer resources and/or a modem connection to the internet.
 
http://raystedman.org/22Stat.txt is a server-status that the aftermath of
all this.  Notice the number of workers that were allocated to this one
user.
 
This consumption of server resource by one user is unfair to everyone else
trying to use http at the same time.  Is it possible to control resource
allocation so that it is fair to all users?
 
Thanks! Greg
 
PS. The user is working on transferring a group of .mp3 files at the same
time. This can be seen at http://raystedman.org/mp3Ref.txt.  The server
doesn't have much else going on which can be seen here
http://raystedman.org/22Ref.txt.

 

Re: Large Resource Consumption by One User Access to mp3 File

[Aaron Bannert <aa...@clove.org>]

Hi Greg,

According to your logs, each of the responses are 206 (Partial Content)
codes, which means the client requested only a range of the resource,
not the entire resource (see
http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.7
for details).

It is unclear from your message how the Apache Service is stopping, or
if it recovers or crashes. If it is crashing, then a bug report would
be greatly appreciated. If it is simply becomming inaccessible for a
brief period, that sounds more likely to be underallocation of resources,
and the user support list will be the best place to address that.

-aaron



On Thu, Feb 08, 2007 at 08:17:09AM -0800, Greg Sims wrote:
> I originally posted this to the User Support forum and received no replies
> in over two weeks.  I appreciate your help with this in advance!
>  
> The Apache Service is stopping as a result of a single user accessing one or
> two mp3 files.  I gathered some log data to detail the problem:
>  
> http://raystedman.org/4204Ref.txt  contains a log sequence that accesses one
> mp3 file by one user.
>  
> http://raystedman.org/mp3/4204.mp3 is the mp3
> <http://raystedman.org/mp3/4204.mp3%20is%20the%20mp3>  being accesses which
> is almost 7 MB large.  
>  
> Normally I will only see one record in the access_log for a transfer like
> this one.  This transfer contains 30+ records over 12 minutes from the same
> user to the same file.  It may be that this user is one a system with
> limited buffer resources and/or a modem connection to the internet.
>  
> http://raystedman.org/22Stat.txt is a server-status that the aftermath of
> all this.  Notice the number of workers that were allocated to this one
> user.
>  
> This consumption of server resource by one user is unfair to everyone else
> trying to use http at the same time.  Is it possible to control resource
> allocation so that it is fair to all users?
>  
> Thanks! Greg
>  
> PS. The user is working on transferring a group of .mp3 files at the same
> time. This can be seen at http://raystedman.org/mp3Ref.txt.  The server
> doesn't have much else going on which can be seen here
> http://raystedman.org/22Ref.txt.
> 
>  
> 

Re: Large Resource Consumption by One User Access to mp3 File

[Joshua Slive <jo...@slive.ca>]

On 2/8/07, Greg Sims <gr...@headingup.net> wrote:

> This consumption of server resource by one user is unfair to everyone else
> trying to use http at the same time.  Is it possible to control resource
> allocation so that it is fair to all users?

The user in question is using some kind of download accelerator that
uses multiple byte-range requests to access the same file
simultaneously over multiple connections.  In general, these
accelerators are designed simply to squeeze out other users and hence
get faster downloads.  It should be considered and handled like a
denial-of-service attack.  Some documentation on that is here:
http://httpd.apache.org/docs/trunk/misc/security_tips.html#dos

In general, either use a firewall to restrict number of connections
per IP, or use a third-party module to do the same.  See
http://modules.apache.org/

Joshua