Volume testing is placing a heavy load on the server, with a high volume of data transfers, for 24 to 48 hours. One way to implement this is to use one set of clients to generate large amounts of new data and another set to verify the data, and to delete data to keep the size of the database at an appropriate level. In such a case, you need to synchronize the verification scripts to wait for the generation scripts. The 4Test script language makes this easy. Usually, you would need a very large test set to drive this type of server load, but if you under-configure your server you will be able to test the sections of the software that handle the outer limits of data capacity.