Virtual Servers

Many sites run VTScada on one or more virtual servers. The technology works well, but beware of the following scenario:

If VTScada is installed on a Virtual Server and then that server is cloned, then both VTScada instances will have the same Machine ID, which is stored in a registry value that VTScada creates. VTScada server redundancy and synchronization processes will not work in this situation. Reinstalling VTScada does not help. This scenario will also lead to duplicate VTScada Serial Numbers. It will also lead to a violation of the VTScada license, which requires one license per computer.

 

You must change the Machine ID registry key on one of the virtual servers. The key is stored in HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Trihedral. The server must be rebooted after making this change. You are advised to contact Trihedral Technical Support before proceeding.

VTScada must be activated on the new virtual server. License activation is unique to a single machine, virtual or otherwise.

(This is similar to the problem that is caused by installing VTScada on a replacement server using a backup created using a disk-imaging program.)

 

VTScada should work on redundant VM platforms where there is a shared disk image among redundant VM's, but may incur data corruption in the situation where a near-realtime backup VM image is spooled up when the running VM image incurs an out-of-service event. The risk relates to the hardware configuration.