Issue
Niagara R2 stations (including Enterprise Server) may experience slow startup, high disk usage, or performance degradation due to excessive historical alarms and trend/archive data. Users need a safe and efficient way to purge old data and restore normal operation.
Product Line
TAC IA Series
Environment
I/A Series R2 Niagara
Cause
Historical alarms and trend/archive data accumulate in the APP folder and station database over time. Large APP folders (>500 MB) or oversized alarm tables increase boot time, consume disk space, and impact station performance.
Resolution
Two recommended approaches:
Option 1: APP Folder Reset (Complete Purge)
Removes all archived alarms, trends, and logs.
Steps:
- Stop Niagara Service:
- Control Panel → Administrative Tools → Services → Stop Niagara
- Rename or Delete APP Folder:
- Path:
C:\Niagara\stations\[station name]\app - Preferred: Rename (e.g.,
app_backup_YYYYMMDD) for rollback
- Path:
- Restart Niagara Service:
- Services → Start Niagara
Result: Station recreates a fresh APP folder; archiving resumes from zero.
- Services → Start Niagara
Option 2: SQL Query (Selective Purge)
Removes specific alarm history while retaining other logged data.
Steps:
- Access query form:
http://[ipaddress]/appdb/queryForm - Execute SQL:
delete from event.eventhistory - Repeat for other tables as needed (see SQL_Tutorial\QueryExamples_10_6_04.pdf).
Note: May take time for large databases.
Best Practices & Warnings
- Backup first: Zip or copy APP folder before deletion.
- Maintenance window: Perform during low-impact periods.
- Data retention compliance: Confirm customer requirements before purging.
- Verify after restart: Ensure alarms and trends resume logging correctly.
