Applies To:
  • CitectSCADA 1.x, 2.x, 3.x, 4.x, 5.x
Summary:
Question: Will my trend files on the standby server always be identical to those on the primary server? 

Solution:
Under most normal conditions, the trend files will be identical on the primary and standby trend servers. However, under some special cases the trend files may have some gaps. Consider the following scenario:

When the standby server becomes operational, it copies the trend info from the primary server. The standby then stops operating and soon after the primary fails. The standby begins operation, it cannot update its trend information, because the primary is not operating. The primary then starts operation and updates its information

Because both servers were down at the same time, a gap in the standby's trend files has occurred.

You can avoid the above problem by always keeping one of the trend servers running. If your trend files have a gap in their data, you can recover the data by copying the files from the other trend server. See Q1265 for further information. 
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