Hello @AndrewJ,
first a more general note regarding your persist file, you should not just persist * everything and on top of that every minute. Persist the groups and/or items you are actually interested in with the strategy “everyChange, everyHour”, which should be more than enough for all use cases.
Secondly make sure to configure your service correctly. See InfluxDB+Grafana persistence and graphing
All configurable details are important to get right.
Lastly, please check your log for influxdb related information. If needed increase the loglevel. See: