Thanks for the reply.
My controller is LSI SAS HBA 9300-8i with 8 ports.
If I want to connect 8 SATA SSD drives with HBA 9300-8i ,then I can connect 8 drives(with 2 cables) with 2 ports of HBA.This is called single link.
If I want to connect 4 SATA SSD drives with HBA 9300-8i ,then i can connect 4 drives only with 8087 cable.This is called dual link.
If I use SAS expander,then its not possible ?
Am i right?