Create an OpenMetrics text file from a CSV file that was exportet from TA's Control and Monitoring Interface (C.M.I). The OpenMetrics data can then be backfilled into Prometheus.

• use TA's Winsol to extract historic data from C.M.I. data logger
• export into csv file using TA's Winsol

• run C.M.I. CSV to OpenMetrics conversion, e.g. ./cmi-openmetrics.py <winsol_export.csv> <cmi_id> <job_name> > backfill.om
• Linux optional, depending on the number of metrics and history, increase number of open files limit for the current session ulimit -n 4096 # increase limit for number of open files
• install Prometheus (including promtool)
• run Prometheus backfill command, e.g. promtool tsdb create-blocks-from openmetrics backfill.om ./data --max-block-duration 96h
• copy backfilled data to target machine running Prometheus, e.g. scp -rp ./data <target_machine>:~/

• make a backup of current prometheus data, take a snapshot
• apply corresponding permissions, e.g. running Prometheus via docker with a mounted volume sudo chown -R nobody.nogroup ~/data/
• make sure Prometheus runs with the --storage.tsdb.allow-overlapping-blocks command line flag
• move backfilled data into Prometheus data folder, e.g. running Prometheus via docker with a mounted volume sudo mv ~/data/* ~/prometheus/prometheus/

• Technische Alternative (TA) website
• C.M.I. wiki entry
• https://prometheus.io/docs/prometheus/latest/storage/#backfilling-from-openmetrics-format
• https://tlvince.com/prometheus-backfilling