Optimal Configuration of Front-End
Printing 
Purpose
As with the other output methods, the spool work process performs the processing for front-end printing. Conflicts can occur in your SAP spool system between normal and front-end print requests. Even if you have classified your spool servers and output devices by the type of output for which they are to be used (such as production printing, mass printing) - as SAP recommends ‑ problems can occur with the server workload due to front-end printing.
Process Flow
The way in which you should configure your system to avoid conflicts of this type is explained below.
· If possible, set up two spool work processes on each application server, in particular if you are using front-end printing with control technology (access method G).
To do this, add the profile parameter rdisp/wp_no_spo (number of spool work processes) to the instance profile of the relevant server, and set its value to at least 2.
· Define the maximum number of spool work processes to be used for front-end printing.
By default, a maximum of one spool work process for each spool server is defined for front-end printing; that is, this spool work process can also process front-end print requests.
If a very large quantity of front-end printing is performed in your system, add profile parameter rdisp/wp_no_Fro_max to the instance profile, and increase the number of work processes.
· If you want to reserve spool work processes for front-end printing, you can use the parameter rdisp/wp_no_spo_Fro_min to do this.
The spool work processes reserved with this parameter are then available exclusively for front-end printing.
So that your SAP spool system can process requests as effectively as before despite the reservation, you should increase the number of spool work processes by at least one, as one spool work process is used for front-end printing, by default.
Example: In the instance profile of the spool server mn1234_YXZ_99, the number of spool work processes is defined as 2 using the profile parameter rsdisp/wp_no_spo, and the number of spool work processes reserved for front-end printing is defined as 2 using the profile parameter rdisp/wp_no_spo_Fro_min. Increase the value of rdisp/wp_no_spo to at least 3.
For more information, see SAP Note 351492 in the SAP Service Marketplace.
See also:
Front-End Printing on Local Printers
