I take 2000 IU in the winter, 1000 IU in the summer. It's well below the recommended upper limit.

According to Health Canada the upper tolerable limit of daily Vitamin D intake for Canadian adults is 4000 IU.

Alberta Health Services adds:

Since we can't get enough vitamin D from food to meet our body's needs, Alberta Health Services recommends that all healthy Albertans take a vitamin D supplement. Some people (like those at risk of osteoporosis) need higher amounts of vitamin D.

They also say to check with your doctor, of course.