Adding a SAS hard disk drive in HP Proliant Server with other hard disk drive that is running

[Laritza]

Please a need help I have a HP Proliant Server 360 Gen 9 and I need to add a new SAS hard disk drive and then I need to configure again with the array controller for the mirror 1 but the main problem is that this HP Proliant is running with another disk drive,I need to say I have one disk working and I have another new disk but I need to put this new disk with the mirror configuration,please could you help me,thanks very much I hope a answer