Hello,   It sounds like you are no longer under warranty?   If so, you can't use off the shelf OEM drives with Dell PS Series arrays.  They have a custom image on them from the factory.   The firmware will not allow non-Dell drives to operate.   This will mean you would have to purchase used drives from a third party supplier.   If the drive is EQL certified it will have a qualified and compatible firmware on it.  With proper Dell drives you can mix drive firmware.    Regards, Don  
I need to replace a failed drive in our PS6100. If I purchase a replacement drive, does it need to be the same exact specs? Can the model and firmware be different as long as the drive is still a 600GB, 10K, 2.5" SAS drive? Model: ST9600205SS F/W: CE0B
PS6100 Drive Replacement