As our transaction logs are filling up rapidly, we would like to switch from Full Recovery Mode to Simple Mode.
Will this cause problems with the Foglight Repository?
The Management Server accepts the instance-level default for database recovery (regardless of the recovery model of the model database, which is purely a template used to create new databases). There is no harm in changing the recovery model from full to simple, other than point-in-time recoverability is lost. If you require the ability to perform disaster recovery on your Foglight database, you should use the full recovery model and you should make frequent transaction log backups to ensure that it does not grow beyond an undesirable threshold. If you do not require point-in-time recoverability, you can use the simple recovery model, and there will be no additional ramifications.