The storage limit of Force.com servers depends on the number of licenses and the type of license we have. With Professional and Enterprise user licenses, we get 20 MB/user with a minimum storage of 1 GB, and unlimited user licenses get 120 MB/user. It is highly recommendable that we clean the data periodically to remove unwanted records.

Additional storage can be purchased in blocks of 50 MB and 150 MB from Salesforce.com.