Configure Archives

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.

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.

Use the Microsoft Volume Shadow Copy Service to back up large archive files, or if you want to back up more than the last two archives, as it allows you to backup and restore archives reliably and in a short period of time without affecting the data collection.

The Volume Shadow Copy feature is provided by Windows Operating System, and the instructions to use backup and restore vary depending on the backup application that is used in the Windows operating system.

VSS provides fast volume capture of the state of a disk which is called a snapshot or shadow copy. When the snapshot is taken, disk writes are suspended for a brief period of time, typically on the order of milliseconds. After the snapshot, disk writes can resume, but the original state of the files are maintained by a difference file. The difference file allows the state of the original file at the time of the snapshot to be reconstructed. This behavior allows files to be backed up while new data is being written to files.

If you are using ihArchiveBackup.exe before the upgrade, your backup will continue to work in the same or similar manner as it did before the upgrade. There is no change in the backup procedure and the Auto Recovery Backup Files option remains unchanged.

Microsoft uses a backup format called Virtual Hard Disk (VHD) to back up files.

When you create archives backup using Microsoft Volume Shadow Copy Service, you must first restore the archives files (that is, .bkf or .vhd into .iha) using the Windows Restore wizard, and then restore the archives (.iha) into Historian. For more information on restoring an archive (.iha) into Historian, refer to the Restoring an Archive topic.

Microsoft uses a backup format called Virtual Hard Disk (VHD) to back up files. When you restore archive backups using Microsoft Volume Shadow Copy Service, you must stop the online Historian archiver, convert the shadow archive files (.bkf or .vhd) into archive files (.iha) using the Windows Restore wizard, and then restore the archives (.iha) into Historian.

Historian can store current and backup archive files on remote storage devices. These remote storage devices can consist of network shares, Storage Area Networks (SAN), or Network Attached Storage (NAS) devices. You can also employ a hybrid approach, by storing your current archive on the local disk and writing a script using the Historian SDK to migrate older archives to a remote storage device.

A SAN is a dedicated network apart from a LAN, specifically configured to allow servers to communicate with large storage arrays, usually over fibre-optic cables. The SAN is directly accessible as a disk device to Windows and does not operate through the slower network layer. NAS devices are similar to a SAN, but are directly attached to the LAN, appearing as a server.

If the Data Archiver service is not working, view the Messages page. Messages like these indicate that Historian is trying to use mapped drives: "Path N:\ not found." "Mapped drives unsupported as archive or backup file location" "UNC paths inaccessible when running as LocalSystem, configure other logon account for DataArchiver service". If these messages appear, find and change mapped drives to UNC paths.

Example: Migrating Non-Current Archives to a Remote Location

The following sample VBScript code will migrate non-current archive to a remote location by accessing the Historian SDK. This script could be run at specific intervals to migrate data from a local disk to a network share.

Dim FileSystem
set FileSystem = CreateObject("Scripting.FileSystemObject") Dim remoteLocation
remoteLocation = "\\StorageServer\Historian\Archives"
If InStrRev(remoteLocation, "\") Len(remoteLocation) Then remoteLocation = remoteLocation & "\"
' make sure we can access the remote storage before proceeding
Dim TestFile
set TestFile = FileSystem.OpenTextFile(remoteLocation & "Test.txt", 2, True, 0) If TestFile is Nothing Then
err.Raise 1, , "Unable to access remote storage location" End If
TestFile.Close
FileSystem.DeleteFile remoteLocation & "Test.txt" Dim Server
set Server = CreateObject("iHistorian_SDK.Server") If Server is Nothing Then
err.Raise 1, , "Unable to create iHistorian_SDK.Server object" End If
Dim archivesToMigrate(), i
If Server.Connect() Then
With Server.Archives
Dim backupPath
backupPath = .ArchivingOptions("ArchiveBackupPath")
If InStrRev(backupPath, "\") Len(backupPath) Then backupPath = backupPath & "\" ReDim archivesToMigrate(.Item.Count, 2)
For Each archive in .Item
If Not archive.IsCurrent Then
If UCase(Left(archive.FileName, InStrRev(archive.Filename, "\"))) UCase(remoteLocation) Then i = i + 1
archivesToMigrate(i, 0) = archive.Name 
archivesToMigrate(i, 1) = backupPath & "Offline\" & cstr(archive.Name) & ".zip" archivesToMigrate(i, 2) = archive.FileSizeTarget
End If
End If
Next
Dim j
For j = 1 To i
If .Delete(cstr(archivesToMigrate(j, 0))) Then FileSystem.MoveFile archivesToMigrate(j, 1), remoteLocation Dim archive
set archive = .Add(cstr(archivesToMigrate(j, 0)), cstr("%%inplace%%" & remoteLocation & archivesToMigrat
If Not (archive Is Nothing) Then
FileSystem.DeleteFile remoteLocation & archivesToMigrate(j, 0) & ".zip" End If
End If
Next End With Server.Disconnect
Else
err.Raise 1, , "Failed connecting to server" 
End If