Built up connections and high CPU

Built up connections and high CPU

We have discovered a problem at some customer sites where connections build up which eventually leads to a high CPU state on the webNetwork relay server.

The problem comes from a bug in SSL , Java and Jetty (the internal web server used in webNetwork).

This can happen on version of webNetwork 6.2.1 thu 6.3.0 (current release)

The problem shows up predominately on larger systems where they have thousands and thousands of connections every day.  Some connections in the OS are not getting closed completely and start to get back logged.  The OS starts spending large amounts of time trying to close these connections leading to a high CPU state.

If you use a tool like TCPView (provided in the \stoneware\util\windows) folder you can view the number of TCP connections in the close_wait state.  This is the tcp state that causes the problem.


There are two current work arounds.

1) Schedule periodic restarts of the webNetwork service on the relay. Depending on your usage this could be ever few days or more.

2) If you have a load balancer, you can off load your SSL to the load balancer and that will eliminate the problem.

Stoneware is currently working on a fix which includes an updated Java version along with an updated Jetty web server in the product.  Unfortunately this is not a simple task and is taking many development hours and we are shooting for April to have a update available to customers.


    Can't find the KB

    Unable to find the KB to address your issue ?  

      • Recent Articles

      • Lenovo Unified Workspace End-of-Life Questions and Answers

        Will the shutdown of LUW servers and access to downloads affect my server licensing? No, the shutdown of the customer servers and access to the product and licensing downloads will not affect your server licensing. This license is downloaded and ...

      • How do I determine my Unified Workspace license expiration date?

        The best method for determining the licensing information including the expiration date of your Unified Workspace license: Login to your 8090 management console on each server This may take remoting into each LUW server and relay, opening a browser, ...

      • Lenovo Unified Workspace 7.0.2.13 Released

        Highlights of Unified Workspace 7.0.2.13 Before you install: Please view the installation notes here. 7.0.2.13 requires a 7.0 license file. Below is a list of enhancements and fixes released in Unified Workspace 7.0.2.13 Fixed external storage ...

      • LanSchool Documentation Guides

        LanSchool Classic Teacher Console The LanSchool Teacher Console is the interface teachers will use to manage their classroom and students. It contains all the tools necessary for a teacher to effectively interact with students and create a ...

      • Lenovo Unified Workspace 7.0.1.41 Released

        Highlights of Unified Workspace 7.0.1.41 Before you install: Please view the installation notes here. 7.0.1.41 requires a 7.0 license file. Below is a list of enhancements and fixes for Unified Workspace 7.0.1.41 Updated Log4j Updated Java Updated ...

      • Related Articles

      • How to troubleshoot high cpu on domain controller

        webNetwork uses LDAP to communicate with Microsoft Active Directory.  If your AD servers are underpowered you may see high cpu with the LSASS.exe process. The following information comes from Microsoft ( https://support.microsoft.com/en-us/kb/2550044 ...

      • Number of connections for webRDP Client

        Question: How many RDP connections can my users make, through Unified Workspace, using the webRDP client? Solution: As the webRDP client is very resource intensive, for the UW relay server, we've found that the each relay can handle approximately ...

      • Slow connections when launching app

        When user would launch a published app it would take a while. When closing an app blue screen won't disappear. Web browser was set to prompt when running activex controls. Also found that Time Live was set to 0 which was causing the application to ...

      • How do I use Netstat to see connections

        Netstat has some very useful command line switches that help show the connections into a server.  If you are seeing many TCP TIME_WAITs that are not going away then that tends to indicate an issue, many times a box low on resources tends to build up ...

      • The Terminal Server has exceeded the maximum number of allowed connections

        Customer is getting the message: The terminal server has exceeded the maximum number of allowed connections. This is from your Microsoft Terminal Server / RDS Server and not from webNetwork. However, some things that you can check.  You can get this ...