By default, the recorder is limited to 120 seconds (2 minutes). If you want to make longer recordings you have to increase the limit accordingly. (The limit prevents the Browser-Temp folder from overflowing)
Please note: No more recording is possible when the hard disk is full.
Here you can define how many clips can be stored in the recorder. The setting should not be too high. Clips that you want to keep must be uploaded to the media library. From there they can be shared with the students.