PaperCut is bypassed under heavy print load

  • 7023140
  • 29-Jun-2018
  • 29-Jun-2018

Environment

OES iPrint
iPrint for OES2015 SP1
iPrint for OES2018
iPrint Appliance 3.x

Situation

The following symptoms exist when having this problem:
  1. PaperCut is bypassed
    • iPrint and PaperCut print fine (meaning: print jobs are submitted to the iPrint queue, taken by PaperCut for accounting purposes, then returned to the iPrint queue to be submitted to the physical printer) until too many print jobs are submitted to the iPrint server at the same time.  When this happens, print jobs are not taken by PaperCut; the print jobs go from the client, to the iPrint server, to the physical printer. 
  2. Slow printing
  3. Too many open files message on the terminal console
    • This message may or may not be present on the terminal.  This was observed only once in all the reports of this issue.
  4. Excessive number of help-print-provider processes
    • Within a terminal session (putty or other tool), execute this command:
      • ps -ef | grep iprint
        • If the problem is being experienced, there will be several dozen of the following processes listed:
          • /home/papercut/providers/print/linux-x64/helper-print-provider
        • There should only be a few dozen listed.

Resolution

Workaround:
Copy/paste the following command into a terminal session:
ulimit -n 65536;printf '*\t%shard\t%snofile\t%s65535\n*\t%ssoft\t%snofile\t%s4096' >> /etc/security/limits.conf
This is listed as a workaround (and not a fix) because the limits.conf file is not read by the Print Manager if it is restarted through iManager or restarted as a result of a server reboot.  In other words, the problem will return.

Side Note: If the Print Manager (ipsmd) is restarted through the rcnovell-ipsmd restart command or through an auto restart due to the child ipsmd process crashing, then the limits.conf file is read and the workaround will still be valid.

Fix:
Contact Micro Focus support to obtain a new novell-iprint-server RPM.  The new RPM will need to be installed and the iprintconf.properties will need to be modified:
  1. Install the new RPM provided by Micro Focus Support
  2. Modify the /etc/opt/novell/iprint/conf/iprintconf.properties
    • Add the following line to file to the bottom of the file:
      • max_open_files=2048,4096

Cause

The helper-printer-provider process needs 2 file handles for each print job.  If there are more than 500 print jobs being processed at a time, the default value in the limits.conf file is not enough to handle the load.

Additional Information

The helper-printer-provider process exists in the /home/papercut/ directory.  The helper-printer-provider process is started by iPrint (ipsmd).