Restoring an Offline Process Historian Database Segment in SIMATIC PCS 7

To restore an offline Process Historian database segment (*.bck file) in SIMATIC PCS 7, use the Process Historian Management Console or Database Administration interface rather than executing manual SQL Server RESTORE DATABASE scripts. Detached historical segments produced during automated scheduled backups can be dynamically re-attached directly into the active database catalog, making historical process values, alarms, and batch data available to WinCC OS clients and Information Server without interrupting active runtime archiving.

Database Segment Architecture and Backup File Formats

SIMATIC Process Historian (PH) serves as the centralized, long-term archive repository for SIMATIC PCS 7 and WinCC. The underlying Microsoft SQL Server database partitions historical process values, messages, and batch records into chronological segments (typically configured as weekly or monthly databases).

Each segment transitions through distinct lifecycle phases:
* Active/Writing Segment: The database partition currently receiving runtime archive tags and messages forwarded from OS Servers.
* Closed/Passive Segment: Completed historical time slices stored on the primary hard disk array, accessible for client read queries.
* Backed-up/Detached Segment: Segments that have been backed up to secondary storage (NAS, SAN, or offline volume) and detached from the SQL Server instance to conserve local disk capacity. These are packaged as standalone *.bck files containing SQL Server backup structures combined with PH metadata manifests.
* Offline Segment: Previously detached segment files that reside on external backup media and are cataloged within the PH database index.

Attempting to restore these segments using native Microsoft SQL Server Management Studio (SSMS) scripts bypasses the Process Historian catalog, corrupting internal pointers and preventing WinCC Information Server from querying historical tags across segment boundaries.

Step-by-Step Procedure to Restore and Attach .bck Segments

Follow this procedure to attach historical .bck archive segments into an operational Process Historian system.

Prerequisites

Administrative credentials on the Process Historian operating system (member of Administrators and SIMATIC HMI user groups).
Direct network or local disk access to the folder path housing the required *.bck backup file.
Sufficient contiguous free disk space on the designated Process Historian database drive to accommodate the fully inflated segment database and transaction log files.

Step 1: Open Process Historian Management Console

Log on to the Process Historian server with an account belonging to the local Windows group SIMATIC HMI.
Launch the Process Historian Management Console from the Windows Start menu under Siemens Automation -> Process Historian.
In the left navigation pane, expand the server node and select Database Management (or Backup & Restore depending on the PH version installed).

Step 2: Navigate to Offline Segments

Select the Offline Segments or Archive Segments view.
The grid displays all segments historically generated by this PH installation.
Identify the segment matching the required time window (start date, end date, and segment identifier). If the segment was moved to another medium or was generated prior to a catalog reset, click Add Offline Segment or Browse Segment.

Step 3: Execute the Segment Restore

Right-click the desired segment record and select Restore Segment (or click Restore / Re-attach in the action menu).
If prompted for the archive location, browse to the target directory containing the *.bck file (e.g., D:\PH_Backups\Segments\2023_W12.bck).
Specify the target storage destination on the local disk array for the restored MDF and LDF files.
Click Start Restore. The Process Historian background service invokes the SQL Server restore engine while simultaneously synchronizing its internal metadata catalog.
Monitor the progress bar until the status transitions to Completed Successfully.

Step 4: Verify Catalog Synchronization

Once restored, the segment shifts from the Offline Segments list into the Passive Segments (or Attached Segments) list.
Ensure the state flag indicates Mounted or Attached. Runtime querying is immediately enabled across the historical range.

Verification

In Process Historian Management Console, verify that the restored segment displays a green status icon with state Attached / Ready for Read Operations.
Open the WinCC Information Server web portal, generate a trend or alarm report spanning the time window of the restored segment, and confirm that historical data populates completely without gaps.
On an active WinCC OS Client, open a Trend Control configured to view historical tags, enter a time span within the restored segment, and confirm continuous curve rendering.
Check Windows Event Viewer under Applications and Services Logs -> Siemens -> Process Historian to verify zero database attachment or catalog mismatch errors.

Limitations and Operational Precautions

Restoring multiple weekly segments simultaneously can rapidly exhaust disk capacity on the database storage volume; verify free storage before restoring.
Never use native Microsoft SQL Server Management Studio (SSMS) to attach or restore *.bck files directly into SQL Server, as this breaks PH catalog integration.
Segment backups created on newer Process Historian versions cannot be restored to older PH releases due to Microsoft SQL Server database format incompatibilities.
Restoring offline segments does not disrupt ongoing runtime archiving from active OS servers, provided disk I/O throughput is adequate.

Engineer FAQ

Can I restore a Process Historian segment while runtime archiving is active?
Yes. Process Historian supports online segment restoration. The background restore service mounts the segment as a passive partition without interrupting active data acquisition.
Where does Process Historian store restored database files?
Restored segments are stored in the database directory defined during PH commissioning (typically D:\ProcessHistorian\Database or a dedicated RAID array).
Why does WinCC Information Server show missing data after a segment restore?
If Information Server shows data gaps immediately after restoration, catalog synchronization may still be in progress. Verify that the segment status is Mounted and clear the Information Server reporting cache.
Can I restore .bck files from another PCS 7 project?
No. Process Historian segment files contain unique project GUIDs and cryptographic security identifiers linked to the originating PCS 7 multiproject.
How do I detach the segment after auditing or reporting is complete?
In the Process Historian Management Console, right-click the restored passive segment and select Detach Segment. The database partition will be cleanly detached from SQL Server, freeing disk storage.

Technical References

Siemens Industry Online Support Entry ID 66579062: Process Historian Administration and Maintenance Manual.
Siemens SIMATIC PCS 7 System Documentation: Process Historian Installation and Operation Guide.
Microsoft Docs: SQL Server Database File Detach and Attach Operations.

Restoring an Offline Process Historian Database Segment in SIMATIC PCS 7