Attachment uploads fail after working for some time with "maxThreads" error

Document ID : KB000027224
Last Modified Date : 14/02/2018
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After a few days, Attachment uploads and downloads fail.

There is no response from the Attachment tomcat servlet.

In the file NX_ROOT/log/pdm_tomcat.log the following error is present:

"SEVERE: All threads (75) are currently busy, waiting. Increase maxThreads (75) or check the servlet status".




This can be resolved by tuning the "maxProcessors" variable in the tomcat server.xml file under $NX_ROOT/bopcfg/www/CATALINA_BASE/conf

  1. Open tomcat server.xml with a text editor.

  2. Locate the section for the connector in use; an easy way to identify this is to search for the port in use for tomcat.

  3. Edit the maxProcessors variable as shown below and save the file. The Default value for maxProcessors is 75.
    A recommended starting increase may be to 150 and monitor. Only increase to 300 if the message persists with frequency.
    It is not recommended to make large increases beyond that without supporting evidence.

    <Connector acceptCount="100" className="org.apache.coyote.tomcat4.CoyoteConnector"
    connectionTimeout="20000" debug="0" disableUploadTimeout="true" enableLookups="true"
    maxProcessors="75" minProcessors="5" port="8080" redirectPort="8443" useURIValidationHack="false"/>

  4. After the change, recycle the Service Desk Manager Service.

Additional Information:

For detailed information on "maxProcessors" and each of the variables in the "server.xml" file, please take a look at the documentation at:


For a related Tomcat TEC document, see: When configuring Service Desk for the 'Tomcat port', can we use port 80; as we get an error message telling us to select a different port?