> this is needed, when i show to the participants/student, i need to show him atleast approx. time it takes to finish the course.
You can base it on the average time previous students took to complete the same course. The time it took to complete a course you could calculate from the time they first accessed the course to the time they completed it.
> is the log only option? we have enabled a very small duration to keep the logs. what can we do i this case?
Yes, logs are basically the only option I can see. Something else you might consider are the analytics models (Site administration > Analytics > Analytics Models).
You can base it on the average time previous students took to complete the same course. The time it took to complete a course you could calculate from the time they first accessed the course to the time they completed it.
> is the log only option? we have enabled a very small duration to keep the logs. what can we do i this case?
Yes, logs are basically the only option I can see. Something else you might consider are the analytics models (Site administration > Analytics > Analytics Models).