Although one work data set is sufficient, using two or more work data sets on separate devices usually reduces the elapsed time of the application significantly. In general, using more than three work data sets does not reduce elapsed time any further, and is only necessary if the work data sets are small or the file size is large.

For optimum allocation of resources such as virtual storage, avoid specifying a large number of work data sets unnecessarily.

No more than 255 work data sets can be specified. If you specify more than 32 work data sets, and the Blockset technique is not selected, a maximum of 32 work data sets is used.