title: Apache 2.4.10 hangs AH00485: scoreboard is full, not at MaxRequestWorkers
body: <p>Apache server will stay up for random amount of time, usually days, but eventually enters a hung state. When hung the CPU load gradually spikes on the machine and new web server requests are unresponsive.</p>
  
  <p>Error logs typically contain lots of these:</p>
  
  <blockquote>
    <p>Wed Jan 28 16:06:58.667188 2015] [mpm_event:error] [pid 25336:tid 1] AH00485: scoreboard is full, not at MaxRequestWorkers</p>
  </blockquote>
  
  <p>Environment:</p>
  
  <p>LDOM (VM) SunOS myhostname 5.10 Generic_118833-36 sun4v sparc SUNW,Sun-Fire-T200</p>
  
  <p>http Conf:</p>
  
  <pre><code>StartServers                8
  MinSpareServers             Not set
  MaxSpareServers             Not set
  ServerLimit                 256
  MaxRequestWorkers           100
  MaxConnectionsPerChild      1000
  KeepAlive                   On
  TimeOut                     3000
  MaxKeepAliveRequests        50
  KeepAliveTimeout            2
  </code></pre>
  
  <p>Current non-hung Score Board:</p>
  
  <pre><code>Server Version: Apache/2.4.10 (Unix)
  Server MPM: event
  Server Built: Oct 30 2014 16:29:03
  
  Current Time: Wednesday, 28-Jan-2015 10:59:39 PST
  Restart Time: Wednesday, 28-Jan-2015 09:49:21 PST
  Parent Server Config. Generation: 1
  Parent Server MPM Generation: 0
  Server uptime: 1 hour 10 minutes 17 seconds
  Server load: 0.60 0.46 0.41
  Total accesses: 1134 - Total Traffic: 2.2 GB
  CPU Usage: u9.07 s16.94 cu609.51 cs69.31 - 16.7% CPU load
  .269 requests/sec - 0.5 MB/second - 2.0 MB/request
  1 requests currently being processed, 99 idle workers
  
  PID Connections     Threads Async connections
  total   accepting   busy    idle    writing keep-alive  closing
  25337   0   yes 1   24  0   0   0
  25338   1   yes 0   25  1   0   0
  25339   1   yes 0   25  0   0   1
  25340   1   yes 0   25  0   0   1
  Sum 3       1   99  1   0   2
  </code></pre>
  
  <p>Any thoughts on http conf tuning, OS patches, apache bug fixes appreciated.</p>
  
  <p>Yes I have seen the open ASF bugzilla for the same error message.</p>
  
  <p>This is a production server, so you can imagine, having it go down at random times (usually when I am asleep) is not fun!</p>