Change Virtual Server failed" while modifying Virtual Server properties

Error Message

During restoration of a site, if a user attempts to modify the properties of a Virtual Server, ArcIMS Administrator may display the error "Change Virtual Server failed" together with one of the messages listed below in the ArcIMS Administrator Console.

Cause

The cause is dependant on the accompanying message. See below for more specific information for each possible message.

Solution or Workaround

• "ArcIMS site restoration failed. There could be a problem connecting to a data source. Refer to ArcIMS Knowledge Base for more information."
  
  This condition is encountered when the restoration of a site is not completed either due to a problem with a data source or due to the timeout value in the AppServer.properties file being set very low. This may result in Spatial Server containers being listed as empty, despite them being associated with server instances. The message printed in the AppServerDebug.log when this condition is encountered: "Mismatch in number of threads maintained in server list and requestStores"
  
  Solution 1: The issue may be due to a problem with one of the data sources. If that is the case, then the ArcIMS services Application Server, Monitor and Tasker need to be restarted once the problem is fixed.
  
  Solution 2: The cause of the error may be the duration of time a site takes to restore the site. If that is the case, it is advised to delay any modification of the site until restoration has completed.
• "Cannot add further instances on Spatial Server: S, because it has a SingleThreaded Server".
  
  This condition is encountered when, due to delay in restoration, a container that was associated with a single-threaded server is listed as an empty container in the Admin display. As a result of this, a user may attempt to associate another server (either single- or multi-threaded) with this container. Since this violates the underlying principle of single-threaded servers i.e. an instance of a single-threaded server cannot co-exist with any other instances in a container, the properties of the server cannot be modified.
• "Cannot add further instances on Spatial Server: S, because it already has at least a running Server instance."
  
  In this case, Spatial Server S already contains instances of Servers, and an attempt is made to add a single-threaded server to this Spatial server. This results in the error message shown above being printed.
  The last 2 conditions can best be reproduced when one or more monitors associated with an Application Server are restarted. During restoration, if the properties of the Virtual Servers and containers are viewed in the Admin, non-empty containers are sometimes seen as empty due to them not being restored completely as yet. In this situation, if an attempt is made to add a Virtual Server to these containers, depending on the single-threaded properties of both the Virtual Server that is being added and/or the Virtual Servers currently associated with the container, one of the messages listed in 2 and 3 will be displayed in the Admin Console. During this time, the first message will also occur sporadically.