TN - 1242 Aveva Historian Storage Locations and Best Practices

Description

This article from InSource explains the different storage folders, their structures, how they are used, and important facts to know to ensure the integrity of the data and to prevent data loss.

• Author: Frank Ross
• Published: 03/25/2022
• Applies to: Aveva (Wonderware) Historian

Details

Aveva Historian Storage Locations (Folders Explained) & Best Practices

Upon installing and configuring the Aveva Historian on a server, the Configurator installation process builds several storage folders, typically on the C drive, unless otherwise noted.   Often, customers will designate and dedicate an entire alternate drive for maintaining the Historian data (called data blocks). 

The standard set of Historian folders created, as part of the Configurator process includes:

Circular, Alternate, Permanent, Buffer.     If your company is using an Aveva Historian, it is critically important to understand the purpose of each storage folder, and how the data is managed within accordingly.  

This tech note provided a simple fast definition of each folder.

Circular [C:\Historian\Data\Circular]

•          Mandatory storage location
•          Must be a local drive on the server
•          Used for main historical data storage
•          Data stored as history blocks in subfolders by date
•          Data written in a “circular” fashion, meaning as the storage reaches its limit or is running out of space, the oldest data will be deleted so that new data can be added to the folder

  Alternate [C:\Historian\Data\Alternate]

•          Optional storage location in that it does not have to be configured
•          Used to move the oldest storage blocks out of the Circular and into the Alternate folder.  This happens if (1) the Alternate folder is configured and (2) the Circular folder threshold has been exceeded.
•          This folder is also managed in circular fashion when the capacity of the folder is exceeding the thresholds of the system configuration.   Oldest data is removed from the folder.

Permanent [C:\Historian\Data\Permanent]

•          Optional storage location
•          Purpose is store specific type of critical data but not in a circular buffer format
•          The Historian subsystem will never try to delete or move the data stored in the Permanent folder.

Buffer [C:\Historian\Data\ Buffer]

•          Optional storage location.
•          Used for temporary purposes as in pulling data blocks from a data archive which is not part of the Circular folder.
•          The data in this folder is considered temporary.  
•          The Historian subsystem will never attempt to delete data from this storage partition.

Other Considerations

•          The data owners and managers should ensure timely backups of each of these folders is occurring on a regular basis.
•          It is important to be knowledgeable about the storage frequencies for your Historian application to ensure enough disk space is available to prevent data being removed by the Historian subsystem.  
•          Data should be archived and removed from the Circular folder based on the historical storage requirements by the data owner. 
•          While the data is being stored in proprietary data blocks, it is also important to back up the SQL Server Runtime database on a regular basis.  

Additional information about maintaining the Historian data can be found in the Aveva (Wonderware) Historian Administration Guide. 

Historian Storage Health Check provided by the System Management Console: