The maximum drive we have available for the 1950 is a 500gb drive. It will support the 4 300GB drives without issue. There is a limitation of 2TB per array, but that isn't the controllers limitation. It is a common limitation on some OS's to be able to see and use the array.
What is the maximum drive size for 2.5" SAS drives on a PE 1950 with PERC 6iR? Is there a BIOS limitation? I want to put 4 - 300GB 2.5" SAS drives in one server.  
maximum drive size for 2.5 inch SAS drives for PE 1950