Backups
The use of imaging (cloning) software to restore a lost VTScada server in a multi-server installation can cause significant configuration damage, not just on the machine being restored, but on all machines in your VTScada network.
Trihedral strongly advises you to avoid using such software for your VTScada backups.
Your VTScada application and your application data should be considered separately when designing a backup system.
Recommended (Online Backup):
If your application runs on two or more workstations, where one is designated the primary server and one or more others are designated as backup servers, then your application and your logged data are automatically stored and updated on all configured servers continuously.
If one server fails, install a replacement, do a Get From Workstation to load the application on it, and let VTScada synchronize the data from the current primary server. All of this can be done without interrupting the application. This is the most reliable method available for maintaining a backup of your logged data including operator notes and retained variables and is strongly recommended.
In this configuration, DO NOT use a copy or backup of the data directory to restore data to one server. Doing so will create a discontinuity between the computer that is being restored and the one(s) on which VTScada has been continuing to run. A ChangeSet should not be used to restore a single computer that is part of a VTScada network - always use Get From Workstation to obtain a current copy from another server instead.
DO NOT use imaging software to re-install VTScada and your application on any server.
Alternative Options / Offline Backups:
If you are running VTScada on a single computer only, or if there is a chance that all servers could be lost in an event such as a fire, then you should do the following:
Create a full (standard) ChangeSet of your application on a regular basis and store that ChangeSet file in a secure location, preferably off-site. If you do not have a copy of the VTS or VTScada installation program, a copy matching your last version can be obtained from Trihedral. Snapshot ChangeSets are not suitable for this purpose.
ChangeSet files do not include data or workstation & user - specific settings.
A ChangeSet should never be used to restore one workstation within a networked application. Use the Get From Workstation option in the Add Applications Wizard instead. See: ChangeSets for Distribution
Unless otherwise configured(*), VTScada stores logged data in a folder within your application. For example, if you have installed VTScada in the folder, C:\VTScada and are running an application named MyApp, then the history can be found in:
C:\VTScada\MyApp\Data\
Copy the Data folder and all of its sub-folders.
(*)If you have configured your system to use a 3rd party database program for your logged data instead of the VTScada history system, use the instructions in that program for creating and restoring backups.
Warning: If at all possible, VTScada should be stopped before the data folder backup is made. There are three reasons for this:
- Write-access to the files will be blocked while they are being copied, potentially resulting in the loss of data or damage to the integrity of the system.
- Because VTScada is continually writing data, the backup you create will be out of date by the time the process is complete. Worse, files copied earlier may be out of sync with files copied later during the backup.
- The backup process can be demanding on system resources, possibly interfering with normal VTScada operations.
If it is not possible to stop VTScada before copying the data folder files, use a shadow backup solution.
Again, your best solution for maintaining a backup of the application and all data files is to have primary and backup VTScada servers.
ChangeSets for Distribution - A way to keep a copy of your application itself (excluding logged data).
