iPrint printers frequently changing status from Available to Not Available

  • 7006806
  • 09-May-2012
  • 21-Nov-2012

Environment

Novell iPrint for Linux

Situation

Some or all of the following symptoms are seen (usually during peak printing times):
  • iPrint printers installed to workstations frequently change their status from Available to Not Available.
  • Apache utilization on the server hosting iPrint is at 100% or above.
  • Several dozen Apache child processes show:
    • ps -ef | grep httpd
  • Print Manager Internal Statistics show "Max Number of Threads" at 100.

Resolution

The cause and fix are under investigation.  Until a solution is available, the following Apache configuration changes might alleviate some of the symptoms by allowing Apache to handle a larger load:

Increase Apache Time Out Values:
  • Edit the following lines in the /etc/apache2/server-tuning.conf
    • from
      • MaxKeepAliveRequests 100
      • KeepAliveTimeout 15
    • to
      • MaxKeepAliveRequests 300
      • KeepAliveTimeout 150
  • Save the changes.
  • Restart Apache (rcapache2 restart)
Increase number of Apache MaxClients
  • Verify whether the server is running "worker" or "prefork" multi-processor modules (or MPM).
    • Run /usr/sbin/httpd2 -l (that's a lower case L).  You should see output similar to:

      Compiled in modules:
         core.c
         worker.c  (or prefork.c will show here)
         http_core.c
         mod_so.c

    • If the second line indicates worker.c, the server is running worker MPM.
    • If the second line indicates prefork.c, the server is running prefork MPM.
  • Edit the /etc/apache2/server-tuning.conf file.
    • If the server is running worker MPM, increase the MaxClients under"# worker MPM " by 50 threads (not to exceed 400).
    • If the server is running prefork MPM (the default), increase the MaxClients under"# prefork MPM " by 50 threads (not to exceed 400).
  • Restart Apache (rcapache2 restart)