Hi [NAME],   The DPN# 5MGN8 is not suitable for SC4020. It seems it is only for SC2000 series. 
Hi my SC4020 had 2 folder disk group, one is 10K disk, another is Read-intensive SSD, the read-intensive SSD is 0-5, now I add 5pcs SSD disk, same with the old, I can't assign to the read-intensive SSD group. how can i do. thanks a lot.  
can't add new SSD disk toe read-intensive ssd folder