Create a Buffer Pool named HFXBP with the calculated page size:
Open IBM DB2 Control Center
Expand Databases > WFMDB
Right click Bufferpools and select Create from the shortcut menu
In the Create Buffer Pool dialog box, do the following:
For the Buffer Pool field, type the name of the Buffer Pool (No specific name is required, but IBM WebSphere BI Monitor recommends HFXBP as the Buffer Pool name).
In the Page Size combo box select a number that equal to the calculated page size you calculated in the previous steps, then click OK.
Bounce the DB2 Instance.