SCADA Log Stops Overnight? Check Disk Space and Rotation Limits
A logging process can keep running while new records stop reaching disk. Monitor storage capacity, write errors, and rotation behavior together.
Original capacity example; platform logging and retention requirements vary.
What is happening?
Log rotation divides output into bounded files, but total retention and storage growth still depend on configuration. Other files on the same volume can consume space. A healthy application status does not guarantee successful durable logging.
Check these five things
-
Review write errors and the last successful record time.
-
Check available space on the actual destination volume.
-
Inspect rotation size, interval, and retained-file count.
-
Estimate growth from observed logging rate.
-
Define an alert before the storage margin is exhausted.
Worked example
A teaching logger produces 50 MB per hour. Keeping 48 hours requires about 2.4 GB before filesystem overhead or other data. A 1 GB free-space margin cannot support that retention target if no old files are removed according to policy.
Quick diagnostic reference
| Measure | Purpose |
|---|---|
| Write errors | Detect lost recording |
| Free capacity | Estimate remaining margin |
| Retention policy | Bound expected growth |
The mistake to avoid
Do not delete logs indiscriminately to restore space. Preserve required evidence and follow the approved retention and backup policy.
How to verify the fix
Test rotation and low-space handling in a disposable environment. Confirm alerts arrive while enough capacity remains for the planned response.
Field-work boundary: These are educational diagnostic guides. Use the exact equipment manuals and approved site procedures. Electrical testing and machinery changes belong to qualified, authorized personnel; control hazardous energy and validate affected functions before release.
Technical reference
Python documentation: Rotating file handlers. The examples and diagnostic tables above are original teaching material; they do not replace the product manual.