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  1. #1
    Join Date
    Feb 2005
    Posts
    41

    What's this: Server Reached Maxclients setting

    Hi everyone,

    My httpd were down 4 times in less than a month. Each downtime took about half to an hour for my sites to get backup.

    Before this, the tech from my hosting company showed me this log:


    Apache/1.3.37 (Unix)
    mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 PHP/4.4.4
    FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.28 OpenSSL/0.9.7a configured --
    resuming normal operations [Tue Dec 12 21:56:01 2006] [notice] suEXEC
    mechanism enabled (wrapper: /usr/local/apache/bin/suexec) [Tue Dec 12 21:56:01
    2006] [notice] Accept mutex: sysvsem (Default: sysvsem) [Tue Dec 12 21:56:20
    2006] [error] server reached MaxClients setting, consider raising the
    MaxClients setting


    Now as I'm writing, I keep on getting error messages from Cpanel via email about httpd being down. My sites have been down for an hour already.


    What's the cause of all these? Is it due to overload?

    And how do I solve the problem?


    ps: My server is dedicated - p4 3.4gig dual core with 2 gig ram.

  2. #2
    Join Date
    Oct 2003
    Location
    Chicago, IL
    Posts
    654
    From the logs, it looks like you are hitting the maximum number of simultaneous requests that Apache can serve. This is set to 150 by default. You can raise it by editing /usr/local/apache/conf/httpd.conf and look for the line that starts with "MaxClients" than raise it and restart Apache.
    Zac Cogswell
    WiredTree Fully Managed VPS and Dedicated Hosting | Average Helpdesk Response <15 Minutes, 24x7 Instant Phone Support
    Follow us on Twitter: @WiredTree | Like us on Facebook: facebook.com/WiredTree
    zac @ wiredtree.com | toll-free: 1.866.523.8733 local: +1.312.447.0510

  3. #3
    Join Date
    Oct 2004
    Location
    Kerala, India
    Posts
    4,750
    It means that you arehaving more connections to apache than allowed in the httpd.conf
    You can see the value in the /usr/local/apache/conf/httpd.conf
    In this file look for the directive MaxClients
    This directive tells apache how much connections should be allowed to your web server.
    You will need to check what is the currebt value and has to think about raising this value. But if you have a fairly good value here, there might be a chance for an attack. May be too many connections to the port 80.
    I hope it is clear now. Shoot any questions if you have.
    David | www.cliffsupport.com
    Affordable Server Management Solutions sales AT cliffsupport DOT com
    CliffWebManager | Access WHM from iPhone and Android

  4. #4
    Join Date
    Feb 2005
    Posts
    41
    Thanks everyone for your replies.

    When I first experienced this, my host did an investigation and said my server was Dos attacked. He then blocked the offending IP.

    Now it's about hitting the maximum connection of Apache.

    But I'm still not clear on this:

    Can you give me an example of an activity that contributes to such high connections?

    Can it be due to high traffic connections to one of my sites? One site of mine offer downloads and streaming of video and audio files. Many other sites do hotlink to my server too. Can it be due to this?

  5. #5
    Join Date
    Oct 2003
    Location
    Chicago, IL
    Posts
    654
    Yes, it can be simply because you are getting a lot of traffic to your site. The more traffic to your site, the more connections Apache will have open. It could also be due to a DOS attack. It's hard to say what exactly the cause is without monitoring the traffic.
    Zac Cogswell
    WiredTree Fully Managed VPS and Dedicated Hosting | Average Helpdesk Response <15 Minutes, 24x7 Instant Phone Support
    Follow us on Twitter: @WiredTree | Like us on Facebook: facebook.com/WiredTree
    zac @ wiredtree.com | toll-free: 1.866.523.8733 local: +1.312.447.0510

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