Configure Archives

Historian archives are stored data files, each of which contains data gathered from all data sources during a specific period of time. There are two types of archive files in an Historian archives directory:
  • machine name_Config.ihc : a single .IHC file containing information about the archiver, tag configuration, and collector configuration.
  • machine name_ArchiveXXX.iha: an archive data file where x is a number indicating the place of the file in a time-based sequence.

Archive files grow to a user-configured maximum size as data is recorded by the server. Historian will asynchronously create a new empty archive when data starts loading into an existing archive. Whenever the current archive becomes full, Historian will immediately serve data to a newly created archive. This significantly reduces archive creation and transition time. If the automatic create archive option is not enabled, however, you must open a new archive manually.

Note: If the Automatic create archive option is not enabled and you do not create a new archive manually, or if the available disk space is less than the required amount of free disk space, then a new archive will not be created.

If you enable the Overwrite Old Archives option, the system replaces the oldest archived data with new data when the latest archive default size has been reached. Since this action deletes historical data, exercise caution in using this feature. Be sure that you have a backup of the archive so that you can restore it later. Best practice is to create an additional archive to prevent premature loss of data due to overwriting. For example, if you want to save 12 months of data into 12 archives, create 13 archives.

During archiver startup and every 60 seconds while the server is running, Historian checks to make sure you have configured enough free disk space to save the archives, buffer files, and log files. If there is insufficient disk space, the Data Archiver shuts down and a message is logged into the log file. By default, you can view the Historian archiver log file in C:\Historian Data\LogFiles

[03/03/10 15:28:41.398] Insufficient space available in [d:\Historian\Archives\] 
        [03/03/10 15:28:41.399] The server requires a minimum of [5000 MB] to continue 
        [03/03/10 15:28:41.679] USER: DataArchiver TOPIC: ServiceControl MSG: DataArchiver(DataArchiver)
        Archiver shutdown at 03/03/10 15:28:41.653   
        [03/03/10 15:28:41.807] DataArchiver Service Stopped. 
        [03/03/10 15:28:41.809] [d:\Historian\LogFiles\DataArchiver-34.log] Closed.